Glycogen is a branched polymer of glucose that acts as a store of energy in times of nutritional sufficiency for utilization in times of need. Its metabolism has been the subject of extensive investigation and much is known about its regulation by hormones such as insulin, glucagon and adrenaline (epinephrine). There has been debate over the relative importance of allosteric compared with covalent control of the key biosynthetic enzyme, glycogen synthase, as well as the relative importance of glucose entry into cells compared with glycogen synthase regulation in determining glycogen accumulation. Significant new developments in eukaryotic glycogen metabolism over the last decade or so include: (i) three-dimensional structures of the biosynthetic enzymes glycogenin and glycogen synthase, with associated implications for mechanism and control; (ii) analyses of several genetically engineered mice with altered glycogen metabolism that shed light on the mechanism of control; (iii) greater appreciation of the spatial aspects of glycogen metabolism, including more focus on the lysosomal degradation of glycogen; and (iv) glycogen phosphorylation and advances in the study of Lafora disease, which is emerging as a glycogen storage disease.

1. In sodium-free solution electrical constants of short Purkinje fibres were similar to those in Tyrode solution. Alterations in the extracellular calcium concentration ([Ca](o) = 0; 1.8; 7.2 mM) had no appreciable effect on these constants, unless the fibres were soaked in calcium-free solution for more than 40 min.2. In sodium-free solution without calcium there was constant or increasing outward current in response to sudden depolarizations (voltage-clamp technique) over the whole voltage range -85 to +40 mV. In calcium-containing solution initial outward current was followed by a slow change in current towards zero which was sometimes large enough to produce a net inward current. This current had a threshold in the voltage range -60 to -40 mV. It was not affected by alterations in the extracellular chloride or magnesium concentrations. The dependence on [Ca](o) suggests that the slow inward current is carried by calcium ions.3. Negative slopes in the steady-state current-voltage relations were obtained in fibres soaked in calcium-containing solutions but were never observed in calcium-free solution.4. The calcium equilibrium potential (E(Ca)) was estimated to be about 150 mV, inside positive.5. In Tyrode solution the slow inward current was smaller than in sodium-free solution and its threshold was shifted to about -20 to -10 mV. It was dependent on [Ca](o) as in sodium-free solution. It was increased by adrenaline and not affected by tetrodotoxin.6. It is concluded that calcium ions carry an appreciable membrane current in the inward direction when the membrane of the Purkinje fibre is depolarized. This calcium current may be involved in excitation-contraction coupling.

Studies were made of the active ion transport by the isolated urinary bladder of the European toad, Bufo bufo, and the large American toad, Bufo marinus. The urinary bladder of the toad is a thin membrane consisting of a single layer of mucosal cells supported on a small amount of connective tissue. The bladder exhibits a characteristic transmembrane potential with the serosal surface electrically positive to the mucosal surface. Active sodium transport was demonstrated by the isolated bladder under both aerobic and anaerobic conditions. Aerobically the mean net sodium flux across the bladder wall measured with radioactive isotopes, Na(24) and Na(22), just equalled the simultaneous short-circuit current in 42 periods each of 1 hour's duration. The electrical phenomenon exhibited by the isolated membrane was thus quantitatively accounted for solely by active transport of sodium. Anaerobically the mean net sodium flux was found to be slightly less than the short-circuit current in 21 periods of observation. The cause of this discrepancy is not known. The short-circuit current of the isolated toad bladder was regularly stimulated with pure oxytocin and vasopressin when applied to the serosal surface under aerobic and anaerobic conditions. Adrenaline failed to stimulate the short-circuit current of the toad bladder.

Platelets are small disc-shaped cell fragments which undergo a rapid transformation when they encounter vascular damage. They become more spherical and extrude pseudopodia, their fibrinogen receptors are activated, causing them to aggregate, they release their granule contents, and eventually form a plug which is responsible for primary haemostasis. Activation of platelets is also implicated in the pathogenesis of unstable angina, myocardial infarction and stroke. Here we show that platelets from mice deficient in the alpha-subunit of the heterotrimeric guanine-nucleotide-binding protein Gq are unresponsive to a variety of physiological platelet activators. As a result, G alpha(q)-deficient mice have increased bleeding times and are protected from collagen and adrenaline-induced thromboembolism. We conclude that G alpha(q) is essential for the signalling processes used by different platelet activators and that it cannot be replaced by G alpha(i) or the beta gamma subunits of the heterotrimeric G proteins. G alpha(q) may thus be a new target for drugs designed to block the activation of platelets.

1. Intracellular recording of the transmembrane potential in mouse pancreatic cells revealed a membrane potential of -20.1 +/- 0.8 mV for islet cells and -41.2 +/- 1.4 mV for acinar cells.2. The membrane potential of islet cells was glucose dependent and in the absence of glucose the cells hyperpolarized to -32.7 mV; with glucose 27.7 mM they depolarized to -16.1 mV.3. Above a threshold concentration of glucose (4 mM) small action potentials of amplitude 1-4 mV were induced in islet cells. The percentage of cells impaled exhibiting action potentials reached a maximum of 80% at 27.7 mM glucose.4. Mannose 16.6 mM was similar to glucose in its ability to induce action potential discharge in islet cells.5. 2,4-Dinitrophenol (0.25 mM) hyperpolarized islet cells and blocked electrical activity induced by glucose 11.1 mM.6. Adrenaline (1 muM) completely blocked glucose-induced electrical activity but without altering the membrane potential.7. The origin and functional significance of glucose-induced electrical activity in islet cells is discussed in relation to insulin secretion.

BACKGROUND

The unpredictability of anaphylactic reactions and the need for immediate, often improvised treatment will make controlled trials impracticable; other means must therefore be used to determine optimal management.

OBJECTIVE

This study aimed to investigate the circumstances leading to fatal anaphylaxis.

METHODS

A register was established including all fatal anaphylactic reactions in the UK since 1992 that could be traced from the certified cause of death. Data obtained from other sources suggested that deaths certified as due to anaphylaxis underestimate the true incidence. Details of the previous medical history, the reaction and necropsy were sought for all cases.

RESULTS

Approximately half the 20 fatal reactions recorded each year in the UK were iatrogenic, and a quarter each due to food or insect venom. All fatal reactions thought to have been due to food caused difficulty breathing that in 86% led to respiratory arrest; shock was more common in iatrogenic and venom reactions. The median time to respiratory or cardiac arrest was 30 min for foods, 15 min for venom and 5 min for iatrogenic reactions. Twenty-eight per cent of fatal cases were resuscitated but died 3 h-30 days later, mostly from hypoxic brain damage. Adrenaline (epinephrine) was used in treatment of 62% of fatal reactions but before arrest in only 14%.

CONCLUSIONS

Immediate recognition of anaphylaxis, early use of adrenaline, inhaled beta agonists and other measures are crucial for successful treatment. Nevertheless, a few reactions will be fatal whatever treatment is given; optimal management of anaphylaxis is therefore avoidance of the cause whenever this is possible. Predictable cross-reactivity between the cause of the fatal reaction and that of previous reactions had been overlooked. Adrenaline overdose caused at least three deaths and must be avoided. Kit for self-treatment had proved unhelpful for a variety of reasons; its success depends on selection of appropriate medication, ease of use and good training.

BACKGROUND

Although pharmacological block of the slow, delayed rectifier potassium current (IKs) by chromanol 293B, L-735,821, or HMR-1556 produces little effect on action potential duration (APD) in isolated rabbit and dog ventricular myocytes, the effect of IKs block on normal human ventricular muscle APD is not known. Therefore, studies were conducted to elucidate the role of IKs in normal human ventricular muscle and in preparations in which both repolarization reserve was attenuated and sympathetic activation was increased by exogenous dofetilide and adrenaline.

RESULTS

Preparations were obtained from undiseased organ donors. Action potentials were measured in ventricular trabeculae and papillary muscles using conventional microelectrode techniques; membrane currents were measured in ventricular myocytes using voltage-clamp techniques. Chromanol 293B (10 micromol/L), L-735,821 (100 nmol/L), and HMR-1556 (100 nmol/L and 1 micromol/L) produced a <12-ms change in APD while pacing at cycle lengths ranging from 300 to 5000 ms, whereas the IKr blockers sotalol and E-4031 markedly lengthened APD. In voltage-clamp experiments, L-735,821 and chromanol 293B each blocked IKs in the presence of E-4031 to block IKr. The E-4031-sensitive current (IKr) at the end of a 150-ms-long test pulse to 30 mV was 32.9+/-6.7 pA (n=8); the L-735,821-sensitive current (IKs) magnitude was 17.8+/-2.94 pA (n=10). During a longer 500-ms test pulse, IKr was not substantially changed (33.6+/-6.1 pA; n=8), and IKs was significantly increased (49.6+/-7.24 pA; n=10). On application of an "action potential-like" test pulse, IKr increased as voltage became more negative, whereas IKs remained small throughout all phases of the action potential-like test pulse. In experiments in which APD was first lengthened by 50 nmol/L dofetilide and sympathetic activation was increased by 1 micromol/L adrenaline, 1 micromol/L HMR-1556 significantly increased APD by 14.7+/-3.2% (P<0.05; n=3).

CONCLUSIONS

Pharmacological IKs block in the absence of sympathetic stimulation plays little role in increasing normal human ventricular muscle APD. However, when human ventricular muscle repolarization reserve is attenuated, IKs plays an increasingly important role in limiting action potential prolongation.

Anaphylaxis is a clinical emergency, and all healthcare professionals should be familiar with its recognition and acute and ongoing management. These guidelines have been prepared by the European Academy of Allergy and Clinical Immunology (EAACI) Taskforce on Anaphylaxis. They aim to provide evidence-based recommendations for the recognition, risk factor assessment, and the management of patients who are at risk of, are experiencing, or have experienced anaphylaxis. While the primary audience is allergists, these guidelines are also relevant to all other healthcare professionals. The development of these guidelines has been underpinned by two systematic reviews of the literature, both on the epidemiology and on clinical management of anaphylaxis. Anaphylaxis is a potentially life-threatening condition whose clinical diagnosis is based on recognition of a constellation of presenting features. First-line treatment for anaphylaxis is intramuscular adrenaline. Useful second-line interventions may include removing the trigger where possible, calling for help, correct positioning of the patient, high-flow oxygen, intravenous fluids, inhaled short-acting bronchodilators, and nebulized adrenaline. Discharge arrangements should involve an assessment of the risk of further reactions, a management plan with an anaphylaxis emergency action plan, and, where appropriate, prescribing an adrenaline auto-injector. If an adrenaline auto-injector is prescribed, education on when and how to use the device should be provided. Specialist follow-up is essential to investigate possible triggers, to perform a comprehensive risk assessment, and to prevent future episodes by developing personalized risk reduction strategies including, where possible, commencing allergen immunotherapy. Training for the patient and all caregivers is essential. There are still many gaps in the evidence base for anaphylaxis.

The human mind and body respond to stress, a state of perceived threat to homeostasis, by activating the sympathetic nervous system and secreting the catecholamines adrenaline and noradrenaline in the 'fight-or-flight' response. The stress response is generally transient because its accompanying effects (for example, immunosuppression, growth inhibition and enhanced catabolism) can be harmful in the long term. When chronic, the stress response can be associated with disease symptoms such as peptic ulcers or cardiovascular disorders, and epidemiological studies strongly indicate that chronic stress leads to DNA damage. This stress-induced DNA damage may promote ageing, tumorigenesis, neuropsychiatric conditions and miscarriages. However, the mechanisms by which these DNA-damage events occur in response to stress are unknown. The stress hormone adrenaline stimulates β(2)-adrenoreceptors that are expressed throughout the body, including in germline cells and zygotic embryos. Activated β(2)-adrenoreceptors promote Gs-protein-dependent activation of protein kinase A (PKA), followed by the recruitment of β-arrestins, which desensitize G-protein signalling and function as signal transducers in their own right. Here we elucidate a molecular mechanism by which β-adrenergic catecholamines, acting through both Gs-PKA and β-arrestin-mediated signalling pathways, trigger DNA damage and suppress p53 levels respectively, thus synergistically leading to the accumulation of DNA damage. In mice and in human cell lines, β-arrestin-1 (ARRB1), activated via β(2)-adrenoreceptors, facilitates AKT-mediated activation of MDM2 and also promotes MDM2 binding to, and degradation of, p53, by acting as a molecular scaffold. Catecholamine-induced DNA damage is abrogated in Arrb1-knockout (Arrb1(-/-)) mice, which show preserved p53 levels in both the thymus, an organ that responds prominently to acute or chronic stress, and in the testes, in which paternal stress may affect the offspring's genome. Our results highlight the emerging role of ARRB1 as an E3-ligase adaptor in the nucleus, and reveal how DNA damage may accumulate in response to chronic stress.

A model is described in which transient ischemia is induced in rats anaesthetized with N2O:O2 (70:30) by bilateral carotid artery clamping combined with a lowering of mean arterial blood pressure to 50 mm Hg, the latter being achieved by bleeding, or by bleeding supplemented with administration of trimetaphan or phentolamine. By the use of intubation, muscle paralysis with suxamethonium chloride, and insertion of tail arterial and venous catheters, it was possible to induce reversible ischemia for long-term recovery studies. Autoradiographic measurements of local CBF showed that the procedure reduced CBF in neocortical areas, hippocampus, and caudoputamen to near-zero values, flow rates in a number of subcortical areas being variable. Administration of trimethaphane or phentolamine did not affect ischemic and postischemic flow rates, nor did they alter recovery of EEG and sensory-evoked responses, but trimetaphan blunted the changes in plasma concentrations of adrenaline and noradrenaline. Recovery experiments showed that 10 min of ischemia gave rise to clear signs of permanent brain damage, with a small number of animals developing postischemic seizures that led to the death of the animals in status epilepticus. After 15 min of ischemia, such alterations were more pronounced, and the majority of animals died. It is concluded that the short revival times noted are explained by the fact that the model induces near-complete ischemia, and that recovery following forebrain ischemia is critically dependent on residual flow rates during the period of ischemia.

beta-Adrenergic stimulation of the heart is thought to increase cardiac muscle contractility by activation of cyclic AMP-dependent protein kinase and concomitant increase in the phosphorylation of certain proteins (for refs see refs 1-6). Electrophysiological studies have shown that the stimulation of cardiac beta-adrenoreceptors, the external application of cyclic AMP or its analogues to Purkinje fibres, or the injection of cyclic AMP into single myocytes can increase the slow inward current (Isi) during the plateau phase of the action potential (AP). In heart muscle this current is mainly carried by Ca2+ (refs 10, 11) and it has been suggested that cyclic AMP-dependent phosphorylation of some component of the calcium channel increases the amount of Ca2+ which enters the cell during depolarization. We have investigated this hypothesis by examining the electrical responses of isolated guinea pig ventricular myocytes to pressure injections of subunits of the cyclic AMP-dependent protein kinase. We report here that injection of the catalytic subunit (C) resulted in a lengthening of the action potential duration (APD) and an increase in the height of the plateau as well as the amplitude of Isi. By contrast, the injection of regulatory subunit (R) shortened the APD of fast and slow response APs, an effect which was reversed by adrenaline.

1. In epididymal adipose tissue synthesizing fatty acids from fructose in vitro, addition of insulin led to a moderate increase in fructose uptake, to a considerable increase in the flow of fructose carbon atoms to fatty acid, to a decrease in the steady-state concentration of lactate and pyruvate in the medium, and to net uptake of lactate and pyruvate from the medium. It is concluded that insulin accelerates a step in the span pyruvate->>fatty acid. 2. Mitochondria prepared from fat-cells exposed to insulin put out more citrate than non-insulin-treated controls under conditions where the oxaloacetate moiety of citrate was formed from pyruvate by pyruvate carboxylase and under conditions where it was formed from malate. This suggested that insulin treatment of fat-cells led to persistent activation of pyruvate dehydrogenase. 3. Insulin treatment of epididymal fat-pads in vitro increased the activity of pyruvate dehydrogenase measured in extracts of the tissue even in the absence of added substrate; the activities of pyruvate carboxylase, citrate synthase, glutamate dehydrogenase, acetyl-CoA carboxylase, NADP-malate dehydrogenase and NAD-malate dehydrogenase were not changed by insulin. 4. The effect of insulin on pyruvate dehydrogenase activity was inhibited by adrenaline, adrenocorticotrophic hormone and dibutyryl cyclic AMP (6-N,2'-O-dibutyryladenosine 3':5'-cyclic monophosphate). The effect of insulin was not reproduced by prostaglandin E(1), which like insulin may lower the tissue concentration of cyclic AMP (adenosine 3':5'-cyclic monophosphate) and inhibit lipolysis. 5. Adipose tissue pyruvate dehydrogenase in extracts of mitochondria is almost totally inactivated by incubation with ATP and can then be reactivated by incubation with 10mm-Mg(2+). In this respect its properties are similar to that of pyruvate dehydrogenase from heart and kidney where evidence has been given that inactivation and activation are catalysed by an ATP-dependent kinase and a Mg(2+)-dependent phosphatase. Evidence is given that insulin may act by increasing the proportion of active (dephosphorylated) pyruvate dehydrogenase. 6. Cyclic AMP could not be shown to influence the activity of pyruvate dehydrogenase in mitochondria under various conditions of incubation. 7. These results are discussed in relation to the control of fatty acid synthesis in adipose tissue and the role of cyclic AMP in mediating the effects of insulin on pyruvate dehydrogenase.

1. Rates of insulin release, glucose utilization (measured as [(3)H]water formation from [5-(3)H]glucose) and glucose oxidation (measured as (14)CO(2) formation from [1-(14)C]- or [6-(14)C]-glucose) were determined in mouse pancreatic islets incubated in vitro, and were used to estimate the rate of oxidation of glucose by the pentose cycle pathway under various conditions. Rates of oxidation of [U-(14)C]ribose and [U-(14)C]xylitol were also measured. 2. Insulin secretion was stimulated fivefold when the medium glucose concentration was raised from 3.3 to 16.7mm in the absence of caffeine; in the presence of caffeine (5mm) a similar increase in glucose concentration evoked a much larger (30-fold) increase in insulin release. Glucose utilization was also increased severalfold as the intracellular glucose concentration was raised over this range, particularly between 5 and 11mm, but the rate of oxidation of glucose via the pentose cycle was not increased. 3. Glucosamine (20mm) inhibited glucose-stimulated insulin release and glucose utilization but not glucose metabolism via the pentose cycle. No evidence was obtained for any selective effect on the metabolism of glucose via the pentose cycle of tolbutamide, glibenclamide, dibutyryl 3':5'-cyclic AMP, glucagon, caffeine, theophylline, ouabain, adrenaline, colchicine, mannoheptulose or iodoacetamide. Phenazine methosulphate (5mum) increased pentose-cycle flux but inhibited glucose-stimulated insulin release. 4. No formation of (14)CO(2) from [U-(14)C]ribose could be detected: [U-(14)C]xylitol gave rise to small amounts of (14)CO(2). Ribose and xylitol had no effect on the rate of oxidation of glucose; ribitol and xylitol had no effect on the rate of glucose utilization. Ribose, ribitol and xylitol did not stimulate insulin release under conditions in which glucose produced a large stimulation. 5. It is concluded that in normal mouse islets glucose metabolism via the pentose cycle does not play a primary role in insulin-secretory responses.

The illustrated World Allergy Organization (WAO) Anaphylaxis Guidelines were created in response to absence of global guidelines for anaphylaxis. Uniquely, before they were developed, lack of worldwide availability of essentials for the diagnosis and treatment of anaphylaxis was documented. They incorporate contributions from more than 100 allergy/immunology specialists on 6 continents. Recommendations are based on the best evidence available, supported by references published to the end of December 2010. The Guidelines review patient risk factors for severe or fatal anaphylaxis, co-factors that amplify anaphylaxis, and anaphylaxis in vulnerable patients, including pregnant women, infants, the elderly, and those with cardiovascular disease. They focus on the supreme importance of making a prompt clinical diagnosis and on the basic initial treatment that is urgently needed and should be possible even in a low resource environment. This involves having a written emergency protocol and rehearsing it regularly; then, as soon as anaphylaxis is diagnosed, promptly and simultaneously calling for help, injecting epinephrine (adrenaline) intramuscularly, and placing the patient on the back or in a position of comfort with the lower extremities elevated. When indicated, additional critically important steps include administering supplemental oxygen and maintaining the airway, establishing intravenous access and giving fluid resuscitation, and initiating cardiopulmonary resuscitation with continuous chest compressions. Vital signs and cardiorespiratory status should be monitored frequently and regularly (preferably, continuously). The Guidelines briefly review management of anaphylaxis refractory to basic initial treatment. They also emphasize preparation of the patient for self-treatment of anaphylaxis recurrences in the community, confirmation of anaphylaxis triggers, and prevention of recurrences through trigger avoidance and immunomodulation. Novel strategies for dissemination and implementation are summarized. A global agenda for anaphylaxis research is proposed.

Tyrosine hydroxylase catalyses the initial, rate-limiting step in the catecholamine biosynthetic pathway. Catecholamines, which include dopamine, noradrenaline, and adrenaline, are important neurotransmitters and hormones that regulate visceral functions, motor coordination and arousal in adults. The gene encoding tyrosine hydroxylase becomes transcriptionally active in developing neuroblasts during mid-gestation of rodent embryos, before the onset of neurotransmission. Here we show that inactivation of both tyrosine hydroxylase alleles results in mid-gestational lethality: about 90% of mutant embryos die between embryonic days 11.5 and 15.5, apparently of cardiovascular failure. Administration of L-DOPA (dihydroxyphenylalanine), the product of the tyrosine hydroxylase reaction, to pregnant females results in complete rescue of mutant mice in utero. Without further treatment, however, they die before weaning. We conclude that catecholamines are essential for mouse fetal development and postnatal survival.

BACKGROUND

We have developed a multimodal technique for the control of pain following knee and hip surgery, called "local infiltration analgesia" (LIA). It is based on systematic infiltration of a mixture of ropiva-caine, ketorolac, and adrenaline into the tissues around the surgical field to achieve satisfactory pain control with little physiological disturbance. The technique allows virtually immediate mobilization and earlier discharge from hospital.

METHODS

In this open, nonrandomized case series, we used LIA to manage postoperative pain in all 325 patients presenting to our service from Jan 1, 2005 to Dec 31,2006 for elective hip resurfacing (HRA), primary total hip replacement (THR), or primary total knee replacement arthroplasty (TKR). We recorded pain scores, mobilization times, and morphine usage for the entire group.

RESULTS

Pain control was generally satisfactory (numerical rating scale pain score range 0-3). No morphine was required for postoperative pain control in two-thirds of the patients. Most patients were able to walk with assistance between 5 and 6 h after surgery and independent mobility was achieved 13-22 h after surgery. Orthostatic hypotension, nausea, and vomiting were occasionally associated with standing for the first time, but other side effects were unremarkable. 230 (71%) of the 325 patients were discharged directly home after a single overnight stay in hospital.

CONCLUSIONS

Local infiltration analgesia is simple, practical, safe, and effective for pain management after knee and hip surgery.

We have studied the responses to electrical and chemical stimulation of the ventrolateral medulla in the chloralose-anesthetized, paralyzed, artificially ventilated rat. Locations of most active pressor responses were compared to regions containing neurons labeled immunocytochemically for phenylethanolamine N-methyltransferase (PNMT), the enzyme catalyzing the synthesis of adrenaline. Elevations of arterial pressure (+81.6 +/- 2.5 mm Hg) and cardioacceleration (+73 +/- 13.6 bpm) were elicited with low current (5 times threshold of 9.5 +/- 1.1 microA) electrical stimulation in a region of rostral ventrolateral medullary reticular formation we have termed the nucleus reticularis rostroventrolateralis (RVL). Electrical stimulation of the RVL increased plasma catecholamines (16.8-fold for adrenaline, 5.3-fold for noradrenaline, and 1.9-fold for dopamine) and vasopressin (1.7-fold before spinal transection, 4.7-fold after). The location of the most active pressor region in the ventrolateral medulla corresponded closely with the location of C1 adrenaline-synthesizing (PNMT-containing) neurons. In addition, the location of the most active pressor region in the dorsomedial medulla corresponded with the location of a bundle of PNMT-containing axons. Unilateral injections into the RVL of the excitatory amino acid monosodium L-glutamate (50 pmol to 10 nmol), but not saline, caused transient dose-dependent and topographically specific elevations (maximum +71.6 +/- 4.9 mm Hg) of arterial blood pressure and tachycardia. Injections of the rigid structural analogue of glutamate, kainic acid, caused large, prolonged (at least 15 min) pressor responses and tachycardia. Unilateral injections of the inhibitory amino acid gamma-aminobutyric acid (GABA) into the RVL caused transient dose-dependent hypotension (maximum -40.8 +/- 6.6 mm Hg) and bradycardia, whereas the specific GABA antagonist bicuculline caused prolonged (10 to 20 min) elevations (+64.2 +/- 6.8 mm Hg) of arterial pressure and tachycardia. By contrast, injections of the glycine antagonist strychnine had no significant effect. Bilateral injections of the neurotoxin, tetrodotoxin, dropped arterial pressure to low levels (51.7 +/- 4.7) not changed by subsequent spinal cord transection at the first cervical segment (52.5 +/- 6.2). We propose the following. (1) Neurons within the RVL, most probably C1 adrenaline-synthesizing neurons, exert an excitatory influence on sympathetic vasomotor fibers, the adrenal medulla, and the posterior pituitary. (2) These neurons are tonically active and under tonic inhibitory control, in part via GABAergic mechanisms--perhaps via the nucleus of the solitary tract (NTS).(ABSTRACT TRUNCATED AT 400 WORDS)

The purpose of this article is to describe briefly the methods by which the intra-mitochondrial volume may be measured both in vitro and in situ, to summarise the mechanisms thought to regulate the mitochondrial volume and then to review in more detail the evidence that changes in the intra-mitochondrial volume play an important part in the regulation of liver mitochondrial metabolism by glucogenic hormones such as glucagon, adrenaline and vasopressin. It will be shown that these hormones cause an increase in matrix volume sufficient to produce significant activation of fatty acid oxidation, respiration and ATP production, pyruvate carboxylation, citrulline synthesis and glutamine hydrolysis. These are all processes activated by such hormones in vivo. I will go on to demonstrate that the increase in matrix volume is brought about by an increase in mitochondrial [PPi]. This is able to stimulate K+ entry into the matrix, perhaps through an interaction with the adenine nucleotide translocase. The rise in matrix [PPi] is a consequence of an increase in cytosolic and hence mitochondrial [Ca2+] which inhibits mitochondrial pyrophosphatase. In the final section of the review I provide evidence that changes in mitochondrial volume may be important in the responses of a variety of tissues to hormones and other stimuli. I write as a metabolist with a working knowledge of bioenergetics rather than the converse, and this will certainly be reflected in the approach taken. If I cause offence to any dedicated experts in the field of bioenergetic by my ignorance or lack of understanding of their studies I can only offer my apologies and ask to be corrected.

BACKGROUND

Allergic rhinitis is the most common of the allergic diseases. Despite improved understanding of the pathophysiology of allergic rhinitis and advances in its pharmacological treatment, its prevalence has increased worldwide. For patients whose symptoms remain uncontrolled despite medical treatment, allergen injection immunotherapy is advised. An allergen-based treatment may reduce symptoms, the need for medication and modify the natural course of this disease.

OBJECTIVE

To evaluate the efficacy and safety of subcutaneous specific allergen immunotherapy, compared with placebo, for reducing symptoms and medication requirements in seasonal allergic rhinitis patients.

METHODS

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1 2006), MEDLINE (1950 to 2006), EMBASE (1974 to 2006), Pre-MEDLINE, KOREAMED, INDMED, LILACS, PAKMEDINET, Scisearch, mRCT and the National Research Register. The date of the last search was February 2006.

METHODS

All studies identified by the searches were assessed to identify randomised controlled trials involving participants with symptoms of seasonal allergic rhinitis and proven allergen sensitivity, treated with subcutaneous allergen specific immunotherapy or corresponding placebo.

METHODS

Two independent authors identified all studies reporting double-blind, placebo controlled randomised trials of specific immunotherapy in patients with seasonal allergic rhinitis due to tree, grass or weed pollens. Two authors independently performed quality assessment of studies. Data from identified studies were abstracted onto a standard extraction sheet and subsequently entered into RevMan 4.2.8. Analysis was performed using the Standardised Mean Difference (SMD) method and a random-effects model; P values < 0.05 were considered statistically significant. The primary outcome measures were symptom scores, medication use, quality of life and adverse events.

RESULTS

We retrieved 1111 publications of which 51 satisfied our inclusion criteria. In total there were 2871 participants (1645 active, 1226 placebo), each receiving on average 18 injections. Duration of immunotherapy varied from three days to three years. Symptom score data from 15 trials were suitable for meta-analysis and showed an overall reduction in the immunotherapy group (SMD -0.73 (95% CI -0.97 to -0.50, P < 0.00001)). Medication score data from 13 trials showed an overall reduction in the immunotherapy group (SMD of -0.57 (95% CI -0.82 to -0.33, p<0.00001)). Clinical interpretation of the effect size is difficult. Adrenaline was given in 0.13% (19 of 14085 injections) of those on active treatment and in 0.01% (1 of 8278 injections) of the placebo group for treatment of adverse events. There were no fatalities.

CONCLUSIONS

This review has shown that specific allergen injection immunotherapy in suitably selected patients with seasonal allergic rhinitis results in a significant reduction in symptom scores and medication use. Injection immunotherapy has a known and relatively low risk of severe adverse events. We found no long-term consequences from adverse events.

In view of mounting evidence that the suprachiasmatic nucleus (SCN) is directly involved in the setting of sensitivity of the adrenal cortex to ACTH, the present study investigated possible anatomical and functional connections between SCN and adrenal. Transneuronal virus tracing from the adrenal revealed first order labelling in neurons in the intermedio-lateral column of the spinal cord that were shown to receive an input from oxytocin fibres and subsequently second-order labelling in neurons of the autonomic division of the paraventricular nucleus. The latter neurons were shown to receive an input from vasopressin or vasoactive intestinal peptide (VIP) containing SCN efferents. The true character of this SCN input to second-order neurons was also demonstrated by the fact that third-order labelling was present within the SCN, vasopressin or VIP neurons. The functional presence of the SCN-adrenal connection was demonstrated by a light-induced fast decrease in plasma corticosterone that could not be attributed to a decrease in ACTH. Using intact and SCN-lesioned animals, the immediate decrease in plasma corticosterone was only observed in intact animals and only at the beginning of the dark period. This fast decrease of corticosterone was accompanied by constant basal levels of blood adrenaline and noradrenaline, and is proposed to be due to a direct inhibition of the neuronal output to the adrenal cortex by light-mediated activation of SCN neurons. As a consequence, it is proposed that the SCN utilizes neuronal pathways to spread its time of the day message, not only to the pineal, but also to other organs, including the adrenal, utilizing the autonomic nervous system.

1. Small preparations of spontaneously beating rabbit sino-atrial node have been investigated using the two micro-electrode voltage-clamp technique. 2. Hyperpolarizing clamp pulses given from holding potentials of about -45 mV reveal a time-dependent change of a membrane current, if, which is shown to overlap the pace-maker range (-65 mV to -45 mV) for these preparations. 3. The changes in if are shown to be quite distinct from the de-activation of the time-dependent outward current, iK. 4. The time-dependent changes of the if system increase during adrenaline application and therefore contribute to the chronotropic action of adrenaline on the heart. 5. Evidence for a link between slow inward current (iSi) and time-dependent outward current (iK) in rabbit sino-atrial node is presented and assessed.