Proteolytic damage is a late event in the molecular cascade initiated by brain injury. Earlier, we proposed that matrix metalloproteinases (MMPs) and urokinase-type plasminogen activator (uPA) are important in secondary brain injury. We have shown that intracerebral injection of activated 72-kDa type IV collagenase (gelatinase A) opens the blood-brain barrier, and that during hemorrhagic brain injury there is endogenous production of 92-kDa type IV collagenase (gelatinase B) and uPA. Therefore, to study the functional link between proteolytic enzymes and blood-brain barrier damage, we induced MMP expression by infusing tumor necrosis factor-alpha (TNF) intracerebrally in rats. Initially, the effect on capillary permeability of increasing doses of TNF, using [14C]sucrose uptake, was measured. Then, the time-course of the capillary permeability change was studied at 4, 16, 24 and 72 h. Expression of MMP and uPA was measured by zymography at 24 h after TNF injection and compared to saline-injected controls. A dose-dependent increase in capillary permeability was seen 24 h after TNF injection. Maximal uptake of [14C]sucrose occurred at 24 h compared to saline-injected controls (P < 0.05). Zymography showed production of gelatinase B, which was significantly greater than in saline-injected controls at 24 h (P < 0.05). Batimastat, a synthetic inhibitor to metalloproteinases, reduced sucrose uptake at 24 h (P < 0.0001), and was effective even when given 6 h after TNF (P < 0.01). Thus, gelatinase B is the intermediate substance linking TNF to modulation of capillary permeability. Agents that interfere with transcription of proteolytic enzymes or block their action may reduce delayed capillary injury, extending the therapeutic window.

METHODS

The authors investigated the innervation of discographically confirmed degenerated and "painful" human intervertebral discs.

OBJECTIVE

To determine the type and distribution patterns of nerve fibers present in degenerated human intervertebral discs.

BACKGROUND

The innervation of intervertebral discs has previously been extensively described in fetal and adult animals as well as humans. However, little is yet known about the innervation of severely degenerated human lumbar discs. The question may be posed whether a disc that has been removed for low back pain possesses an increased innervation compared with normal discs.

METHODS

The presence of nerve fibers was investigated using acetylcholinesterase enzyme histochemistry, as well as neurofilament and substance P immunocytochemistry. From 10 degenerated and 2 control discs, the anterior segments were excised and their nerve distribution studied by examining sequential sections.

RESULTS

In all specimens, nerve fibers of different diameters were found in the anterior longitudinal ligament and in the outer region of the disc. In 8 of 10 degenerated discs, fibers were also found in the inner parts of the disc. Substance P-immunoreactive nerve fibers were sporadically observed in the anterior longitudinal ligament and the outer zone of the anulus fibrosus.

CONCLUSIONS

Findings indicate a more extensive disc innervation in the severely degenerated human lumbar disc compared with normal discs. The nociceptive properties of at least some of these nerves are highly suggested by their substance P immunoreactivity, which provides further evidence for the existence of a morphologic substrate of discogenic pain.

The co-existence of immunoreactivities to substance P (SP), calcitonin gene-related peptide (CGRP), cholecystokinin (CCK) and dynorphin (DYN) in neurons of the dorsal root ganglion (DRG) of guinea-pigs has been investigated with a double-labeling immunofluorescence procedure. Four main populations of neurons could be identified that contained different combinations of these peptides and had distinctive peripheral projections: (Neurons that contained immunoreactivity to SP, CGRP, CCK and DYN were distributed mainly to the skin. Neurons with immunoreactivity to SP, CGRP and CCK, but not DYN, were distributed mainly to the small blood vessels of skeletal muscles. Neurons with immunoreactivity to SP, CGRP and DYN, but not CCK, were distributed mainly to pelvic viscera and airways. Neurons containing immunoreactivity to SP and CGRP, but not CCK and DYN, were distributed mainly to the heart, systemic blood vessels, blood vessels of the abdominal viscera, airways and sympathetic ganglia. Other small populations of DRG neurons containing SP, CGRP or CCK alone also were detected. Perikarya containing these combinations of neuropeptides were not found in autonomic ganglia. The peripheral axons of neurons containing immunoreactivity to at least SP and CGRP were damaged by chronic treatment with capsaicin. However, some sensory neurons containing CCK alone were not affected morphologically by capsaicin. These results clearly show that individual DRG neurons can contain many different neuropeptides. Furthermore, the combination of neuropeptides found in any particular neuron is related to its peripheral projection.

This study investigated whether a measure of delay discounting was associated with substance use variables in a sample of college students. Participants (N=47) completed a substance use survey and a delay-discounting measure that asked them to make a series of choices between a fixed amount of hypothetical money to be delivered immediately and a larger amount to be delivered after a range of delays. Discounting values were significantly associated with a number of substance use variables, most notably age of first alcohol use (r=-.34; P<.05), age of first smoking (r=-.51; P<.05), age of first marijuana use (r=-.48; P<.05), number of times "passed out" from alcohol use (r=.73; P<.01), and total number of illicit drugs used (r=.32; P<.05). Individuals reporting more illicit drug use and younger ages of first use tend to discount the value of future hypothetical rewards more steeply than their peers.

Not all neuropathic pain patients gain relief from current therapies that include the anticonvulsant, gabapentin, thought to modulate calcium channel function. We report a neural circuit that is permissive for the effectiveness of gabapentin. Substance P-saporin (SP-SAP) was used to selectively ablate superficial dorsal horn neurons expressing the neurokinin-1 receptor for substance P. These neurons project to the brain as shown by retrograde labelling and engage descending brainstem serotonergic influences that enhance spinal excitability via a facilitatory action on 5HT(3) receptors. We show the integrity of this pathway following nerve injury contributes to the behavioural allodynia, neuronal plasticity of deep dorsal horn neurons and the injury-specific actions of gabapentin. Thus SP-SAP attenuated the tactile and cold hypersensitivity and abnormal neuronal coding (including spontaneous activity, expansion of receptive field size) seen after spinal nerve ligation. Furthermore the powerful actions of gabapentin after neuropathy were blocked by either ablation of NK-1 expressing neurones or 5HT(3) receptor antagonism using ondansetron. Remarkably, 5HT(3) receptor activation provided a state-dependency (independent of that produced by neuropathy) allowing GBP to powerfully inhibit in normal uninjured animals. This circuit is therefore a crucial determinant of the abnormal neuronal and behavioural manifestations of neuropathy and importantly, the efficacy of gabapentin. As this spino-bulbo-spinal circuit contacts areas of the brain implicated in the affective components of pain, this loop may represent a route by which emotions can influence the degree of pain in a patient, as well as the effectiveness of the drug treatment. These hypotheses are testable in patients.

OBJECTIVE

To study cumulative exposure to stressors as a risk factor for drug dependence, and evaluate whether group differences in exposure contribute to differences in prevalence.

METHODS

Cross-sectional community survey of life-time adverse experiences and substance and psychiatric disorders.

METHODS

Data collected between 1997 and 2000 in Miami-Dade County, USA.

METHODS

A total of 1803 former Miami-Dade public school students, 93% between ages 19 and 21 years when interviewed. Males and females of Cuban origin, other Caribbean basin Hispanics, African-Americans and non-Hispanic whites are represented equally.

METHODS

Drug dependence disorder assessed by DSM-IV criteria using the Composite International Diagnostic Interview, and a 41-item checklist of life-time exposure to major and potentially traumatic experiences. Both measures include age at time of first occurrence.

RESULTS

Life-time rate of drug dependence disorder (total 14.3%) did not vary significantly (P>> 0.05) by socio-economic group. Male rate (17.6%) was significantly greater than female rate (10.9%). The African-American rate (6.5%) was dramatically lower than non-Hispanic white (17.0%), Cuban (18.1%) and non-Cuban Hispanic (16.0%) rates despite their dramatically higher exposure to adversity. Twenty-eight of 33 individual adversities were associated with the subsequent onset of drug dependence (P < 0.05). Cumulative life-time exposure was greatest for males and for African-Americans, and was associated inversely with socio-economic level. Multivariate discrete-time event history analysis revealed significant independent effects of distal (>1 year earlier) and proximal (previous year) exposure to adverse events (P < 0.05), controlling for childhood conduct disorder, attention deficit hyperactive disorder and previous psychiatric disorder.

CONCLUSIONS

Life-time cumulative exposure to distant as well as more recent adversity predicts risk of subsequent drug dependence, although it does not explain ethnic group differences in risk.

Binding sites labeled by [3H]p-aminoclonidine ([3H]PAC) were characterized in bovine brain membranes prepared from the ventrolateral medulla, the probable site of the antihypertensive action of clonidine and analogs. Comparison was made with [3H]PAC binding to membranes prepared from frontal cortex, which has been studied extensively. Saturation binding isotherms for [3H]PAC were similar in the two regions, although Bmax values were approximately two-fold lower in ventrolateral medulla relative to frontal cortex. Norepinephrine and other phenylethylamines displaced [3H]PAC from a maximum of 70% of the total sites in the ventrolateral medulla. The remaining 30% were norepinephrine-insensitive, non-adrenoceptor sites which displayed high affinity for imidazole compounds. Ligand selectivity differed markedly between ventrolateral medulla and frontal cortex, since some imidazole compounds which potently inhibited [3H]PAC binding in the ventrolateral medulla had no effect in frontal cortex. Imidazole binding sites may mediate, in part, the hypotensive action of clonidine and other imidazole compounds in the ventrolateral medulla. These sites may also participate in the functions of a putative endogenous clonidine-like substance.

OBJECTIVE

Human papillomavirus (HPV) is a common sexually transmitted agent that causes anogenital cancer and precancer lesions that have an inflammatory infiltrate, may be friable and bleed. Our aim was to determine the association between anal HPV infection and HIV acquisition.

METHODS

A prospective cohort study.

METHODS

We recruited 1409 HIV-negative men who have sex with men from a community-based setting in Boston, Denver, New York and San Francisco. We used Cox proportional hazards regression modeling and assessed the independent association of HPV infection with the rate of acquisition of HIV infection.

RESULTS

Of 1409 participants contributing 4375 person-years of follow-up, 51 HIV-seroconverted. The median number of HPV types in HPV-infected HIV-seroconverters was 2 (interquartile range 1-3) at the time of HIV seroconversion. After adjustment for sexual activity, substance use, occurrence of other sexually transmitted infections and demographic variables, there was evidence (P = 0.002) for the effect of infection with at least two HPV types (hazard ratio 3.5, 95% confidence interval 1.2-10.6) in HIV seroconversion.

CONCLUSIONS

Anal HPV infection is independently associated with HIV acquisition. Studies that incorporate high-resolution anoscopy to more accurately identify HPV-associated disease are needed to determine the relationship between HPV-associated disease and HIV seroconversion.

Coronary risk factors, including age, hypertension, diabetes mellitus, hyperlipidemia, and smoking, are associated with enhanced oxidative stress, which is implicated as a potential mechanism for atherogenesis and atherosclerotic cardiovascular diseases. Male sex is one of the well-known cardiovascular risk factors. We tested the hypothesis that oxidative stress is greater in men than in women. Plasma thiobarbituric acid-reactive substances (TBARS) and urinary 8-isoprostaglandin F2alpha (8-iso-PGF2alpha) were measured in 52 young men and 51 age-matched women. The subjects were healthy, were not smokers, and were not taking any medications or vitamins. Age, blood pressure, plasma cholesterol, and glucose did not differ between the groups. Baseline TBARS (2.32 +/- 0.11 [men] versus 1.87 +/- 0.09 [women] nmol/mL, P<0.01) and 8-iso-PGF2alpha (292 +/- 56 [men] versus 164 +/- 25 [women] pg/mg creatinine, P<0.05) were higher in men than in women. Supplementation of antioxidant vitamins for 4 weeks in men produced a significant reduction in TBARS and 8-iso-PGF2alpha by 34% (P<0.01) and 48% (P<0.05), respectively. Plasma superoxide dismutase, catalase, and vitamin E levels were comparable between the groups. Enhanced oxidative stress in men may provide a biochemical link between male sex and atherosclerotic diseases related to oxidative stress.

The present study demonstrates the occurrence of substance P (SP)- and calcitonin gene related peptide (CGRP)-immunoreactive nerve fibres in bone, bone marrow, periosteum, synovial membrane and soft tissues adjacent to the bone. The distribution pattern of the two types of nerves was similar, although the CGRP-positive fibres generally were more numerous. Both types of nerves were particularly abundant near the epiphyseal plate, in the bone marrow of patella and epiphyses, and in the periosteum. Many SP- and CGRP-immunoreactive fibres were also observed around blood vessels.

BACKGROUND

Adolescents' concerns about privacy in clinical settings decrease their willingness to seek health care for sensitive problems and may inhibit their communication with physicians.

OBJECTIVE

To investigate the influence of physicians' assurances of confidentiality on adolescents' willingness to disclose information and seek future health care.

METHODS

Randomized controlled trial.

METHODS

Three suburban public high schools in California.

METHODS

The 562 participating adolescents represented 92% of students in mandatory classes.

METHODS

After random assignment to 1 of 3 groups, the adolescents listened to a standardized audiotape depiction of an office visit during which they heard a physician who assured unconditional confidentiality, a physician who assured conditional confidentiality, or a physician who did not mention confidentiality.

METHODS

Adolescents' willingness to disclose general information, willingness to disclose information about sensitive topics, intended honesty, and likelihood of return visits to the physician depicted in the scenario were assessed by anonymous written questionnaire.

RESULTS

Assurances of confidentiality increased the number of adolescents willing to disclose sensitive information about sexuality, substance use, and mental health from 39% (68/175) to 46.5% (178/383) (beta=.10, P=.02) and increased the number willing to seek future health care from 53% (93/175) to 67% (259/386) (beta=.17, P<.001). When comparing the unconditional with the conditional groups, assurances of unconditional confidentiality increased the number of adolescents willing to return for a future visit by 10 percentage points, from 62% (122/196) to 72% (137/190) (beta=.14, P=.001).

CONCLUSIONS

Adolescents are more willing to communicate with and seek health care from physicians who assure confidentiality. Further investigation is needed to identify a confidentiality assurance statement that explains the legal and ethical limitations of confidentiality without decreasing adolescents' likelihood of seeking future health care for routine and nonreportable sensitive health concerns.

A characteristic peculiarity of the trigeminal sensory system is the presence of two distinct populations of primary afferent neurons. Most of their cell bodies are located in the trigeminal ganglion (TG) but part of them lie in the mesencephalic trigeminal nucleus (MTN). This review compares the neurochemical content of central versus peripheral trigeminal primary afferent neurons. In the TG, two subpopulations of primary sensory neurons, containing immunoreactive (IR) material, are identified: a number of glutamate (Glu)-, substance P (SP)-, neurokinin A (NKA)-, calcitonin gene-related peptide (CGRP)-, cholecystokinin (CCK)-, somatostatin (SOM)-, vasoactive intestinal polypeptide (VIP)- and galanin (GAL)-IR ganglion cells with small and medium-sized somata, and relatively less numerous larger-sized neuropeptide Y (NPY)- and peptide 19 (PEP 19)-IR trigeminal neurons. In addition, many nitric oxide synthase (NOS)- and parvalbumin (PV)-IR cells of all sizes as well as fewer, mostly large, calbindin D-28k (CB)-containing neurons are seen. The majority of the large ganglion cells are surrounded by SP-, CGRP-, SOM-, CCK-, VIP-, NOS- and serotonin (SER)-IR perisomatic networks. In the MTN, the main subpopulation of large-sized neurons display Glu-immunoreactivity. Additionally, numerous large MTN neurons exhibit PV- and CB-immunostaining. On the other hand, certain small MTN neurons, most likely interneurons, are found to be GABAergic. Furthermore, NOS-containing neurons can be detected in the caudal and the mesencephalic-pontine junction portions of the nucleus. Conversely, no immunoreactivity to any of the examined neuropeptides is observed in the cell bodies of MTN neurons but these are encircled by peptidergic, catecholaminergic, serotonergic and nitrergic perineuronal arborizations in a basket-like manner. Such a discrepancy in the neurochemical features suggests that the differently fated embryonic migration, synaptogenesis, and peripheral and central target field innervation can possibly affect the individual neurochemical phenotypes of trigeminal primary afferent neurons.

OBJECTIVE

The study's objectives were to characterize initiation of injection drug use, examine the independent association of specific substance use with injection drug use and determine factors associated with rates of transition from first illicit drug use to first injection among a sample of rural Appalachian drug users.

METHODS

Interview-administered questionnaires were administered to a sample of drug users recruited via respondent-driven sampling.

METHODS

Appalachian Kentucky.

METHODS

Injection drug users (IDUs) (n = 394) and non-IDUs (n = 109).

METHODS

Data were collected on substance use and years from age at initiation of illicit substance use to 'event' (initiation of injection or date of baseline interview for non-IDUs). Logistic regression and Cox regression were used to identify factors associated with life-time injection drug use and transition time to injection, respectively.

RESULTS

OxyContin(®) was involved in nearly as many initiations to injection (48%), as were stimulants, other prescription opioids and heroin combined; for participants who initiated with OxyContin(®), the median time from which they began OxyContin(®) use to their first injection of OxyContin(®) was 3 years. Adjusting for demographics, five prescription drugs (benzodiazepines, illicit methadone, oxycodone, OxyContin(®) and other opiates) were associated with an increased hazard for transitioning from first illicit drug use to first injection drug use (each at P < 0.01).

CONCLUSIONS

In Appalachia, in the United States, the prescription opioid OxyContin(®) is widely used non-medically and appears to show a particularly high risk of rapid transition to injection compared with the use of other illicit drugs.

BACKGROUND

Internet-based cognitive behavioural therapy (iCBT) is an effective and acceptable treatment for depression, especially when it includes guidance, but its treatment adherence has not yet been systematically studied. We conducted a meta-analysis, comparing the adherence to guided iCBT with the adherence to individual face-to-face CBT.

METHODS

Studies were selected from a database of trials that investigate treatment for adult depression (see www.evidencebasedpsychotherapies.org), updated to January 2013. We identified 24 studies describing 26 treatment conditions (14 face-to-face CBT, 12 guided iCBT), by means of these inclusion criteria: targeting depressed adults, no comorbid somatic disorder or substance abuse, community recruitment, published in the year 2000 or later. The main outcome measure was the percentage of completed sessions. We also coded the percentage of treatment completers (separately coding for 100% or at least 80% of treatment completed).

RESULTS

We did not find studies that compared guided iCBT and face-to-face CBT in a single trial that met our inclusion criteria. Face-to-face CBT treatments ranged from 12 to 28 sessions, guided iCBT interventions consisted of 5 to 9 sessions. Participants in face-to-face CBT completed on average 83.9% of their treatment, which did not differ significantly from participants in guided iCBT (80.8%, P = .59). The percentage of completers (total intervention) was significantly higher in face-to-face CBT (84.7%) than in guided iCBT (65.1%, P < .001), as was the percentage of completers of 80% or more of the intervention (face-to-face CBT: 85.2%, guided iCBT: 67.5%, P = .003). Non-completers of face-to-face CBT completed on average 24.5% of their treatment, while non-completers of guided iCBT completed on average 42.1% of their treatment.

CONCLUSIONS

We did not find studies that compared guided iCBT and face-to-face CBT in a single trial. Adherence to guided iCBT appears to be adequate and could be equal to adherence to face-to-face CBT.

Mast cells play a central role in inflammatory and allergic reactions by releasing inflammatory mediators through two main pathways, immunoglobulin E-dependent and -independent activation. In the latter, mast cells are activated by a diverse range of basic molecules, including peptides and amines such as substance P, neuropeptide Y, and compound 48/80. These secretagogues are thought to activate the G proteins in mast cells through a receptor-independent mechanism. Here, we report that the basic molecules activate G proteins through the Mas-related gene (Mrg) receptors on mast cells, leading to mast cell degranulation. We suggest that one of the Mrg receptors, MrgX2, has an important role in regulating inflammatory responses to non-immunological activation of human mast cells.

Opioid and psychostimulant drugs have long been used for the relief of chronic pain in the clinical situation. Animal studies confirm that these drugs alleviate persistent or tonic pain. Little is known, however, about the neural systems underlying the suppression of tonic pain except that they are different from those mediating the suppression of phasic (i.e., sharp and short-lasting) pain. Although spinal and brainstem-descending pain suppression mechanisms play a role in mediating the inhibition of tonic pain, it appears that this response is additionally mediated by the activation of mechanisms lying rostral to the brainstem. Recent studies suggest that the activation of mesolimbic dopamine (DA) neurons, arising from the cell bodies of the ventral tegmental area (VTA) and projecting to the nucleus accumbens (NAcc), plays an important role in mediating the suppression of tonic pain. Other studies suggest that this pain-suppression system involving the activation of mesolimbic DA neurons is naturally triggered by exposure to stress, through the endogenous release of opioids and substance P (SP) in the midbrain.

BACKGROUND

The alcohol dehydrogenase 1B gene (ADH1B) is hypothesized to affect predisposition to alcohol dependence (AD) and abuse. A variant of the ADH1B gene (rs1229984 or Arg48His; previously referred to as Arg [*1] and His [*1]) has been reported to be associated with reduced rates of alcohol and drug dependence. Different studies have produced inconclusive results regarding association between rs1229984 (or rs2066702) and substance dependence.

METHODS

Using the cumulative association study literature from the past 21 years from both English- and Chinese-language publications, this meta-analysis seeks to clarify the contradictory findings and to examine whether the aggregate data provide new evidence of significant association.

RESULTS

The results, based on a large sample size (9638 cases and 9517 controls), suggested strong associations with alcohol dependence and abuse as well as alcohol-induced liver diseases, with an allelic (Arg vs. His) p value being 1 × 10(-36) and odds ratio (OR) (95% confidence intervals [CI]) 2.06 (1.84-2.31) under the random effects model. The dominant and recessive models produced larger ORs of 2.17 and 3.05, respectively. When more stringent criteria and subgroup analyses were imposed, the associations remained consistent and were strongest in various Asian groups (allelic p = 7 × 10(-42) and OR (95% CI) = 2.24 [1.99-2.51] with ORs of 2.16 and 4.11 for dominant and recessive models, respectively).

CONCLUSIONS

Our findings provide further strong evidence for the involvement of the ADH1B gene in the pathogenesis of alcohol dependence and abuse as well as for some alcohol-induced medical diseases in the multiple ethnic populations--in particular, certain Asian populations.

Males of most species are more aggressive than females, but the neural mechanisms underlying this dimorphism are not clear. Here, we identify a neuron and a gene that control the higher level of aggression characteristic of Drosophila melanogaster males. Males, but not females, contain a small cluster of FruM(+) neurons that express the neuropeptide tachykinin (Tk). Activation and silencing of these neurons increased and decreased, respectively, intermale aggression without affecting male-female courtship behavior. Mutations in both Tk and a candidate receptor, Takr86C, suppressed the effect of neuronal activation, whereas overexpression of Tk potentiated it. Tk neuron activation overcame reduced aggressiveness caused by eliminating a variety of sensory or contextual cues, suggesting that it promotes aggressive arousal or motivation. Tachykinin/Substance P has been implicated in aggression in mammals, including humans. Thus, the higher aggressiveness of Drosophila males reflects the sexually dimorphic expression of a neuropeptide that controls agonistic behaviors across phylogeny.

The neuropeptide substance P is a major mediator of neurogenic inflammation and immunomodulatory activities within the central and peripheral nervous system. In several cell types, substance P induces the expression of proinflammatory cytokines that have been implicated in the pathogenesis of different neuropathologies. Substance P preferentially binds to NK-1, a receptor of the neurokinin family, but how the receptor-elicited signal is translated into inflammatory gene expression is not yet understood. In this work, we describe that in U373 MG astrocytoma cells, nanomolar concentrations of substance P potently triggered activation of NF-kappa B, a transcription factor involved in the control of cytokine expression and apoptosis. Substance P-induced NF-kappa B activation was associated with the increased mRNA expression and secretion of IL-8, an NF-kappa B-controlled target gene. The stimulatory effect of substance P was specific, since an NK-1-selective receptor antagonist completely prevented NF-kappa B activation in response to substance P, but not IL-1 beta. In addition, we show that the activity of substance P required mobilization of intracellular calcium and formation of reactive oxygen intermediates as second messengers. Our results suggest that NF-kappa B may be an important component controlling neurogenic inflammation within the peripheral and central nervous system.

Pathological gambling has been termed both the 'pure' and the 'hidden' addiction. 'Pure' because it is not associated with the intake of any addicting substance, and 'hidden' because it is an extension of a common, socially accepted behaviour. The Taq A1 variant of the human DRD2 gene has been associated with drug addiction, some forms of severe alcoholism, and other impulsive, addictive behaviours. We have sought to determine if there is a similar association with pathological gambling. A total of 222 non-Hispanic Caucasian pathological gamblers from multiple sites across the US participated in the study. Of these 171 donated a sample of blood, 127 filled out several questionnaires, and 102 did both. Of the 171 pathological gamblers 50.9% carried the D2A1 allele versus 25.9% of the 714 known non-Hispanic Caucasian controls screened to exclude drug and alcohol abuse, p < 0.00000001, odds ratio (OR) = 2.96. For the 102 gamblers who filled out the questionnaires, 63.8% of those in the upper half of the Pathological Gambling Score (more severe) carried the D2A1 allele (OR versus controls = 5.03), compared to 40.9% in the lower half (less severe). Of those who had no comorbid substance abuse, 44.1% carried the D2A1 allele, compared to 60.5% of those who had comorbid substance abuse. Forty-eight controls and 102 gamblers completed a shorter version of the Pathological Gambling Score. Of the 45 controls with a score of zero, 17.8% carried the D2A1 allele. Of the 99 gamblers with a score of 5 or more, 52.5% carried the D2A1 allele (chi 2 = 15.36, p = 0.00009). These results suggest that genetic variants at the DRD2 gene play a role in pathological gambling, and support the concept that variants of this gene are a risk factor for impulsive and addictive behaviours.

Immunohistochemical and radioimmunoassay studies revealed that both CGRP- and SP-like immunoreactivity in the caudal spinal trigeminal nucleus and tract, the substantia gelatinosa and the dorsal cervical spinal cord as well as in cell bodies of the trigeminal ganglion and the spinal dorsal root ganglion is markedly depleted by capsaicin which is known to cause degeneration of a certain number of primary sensory neurons. Higher brain areas and the ventral spinal cord were not affected by capsaicin treatment. Furthermore CGRP and substance P-like immunoreactivity were shown to be colocalized in the above areas and to coexist in cell bodies of the trigeminal ganglion and the spinal dorsal root ganglia. It is suggested that CGRP, like substance P, may have a neuromodulatory role on nociception and peripheral cardiovascular reflexes.

The apoptotic protein tBid is effective in promoting both leakage and lipid mixing in liposomes composed of cardiolipin and phosphatidylcholine at a molar ratio of 1:2 in the presence of calcium. When half of the phosphatidylcholine component of these liposomes is replaced with phosphatidylethanolamine, a lipid that promotes negative membrane curvature, the rates of both leakage and lipid mixing caused by tBid are substantially increased. Replacement of cardiolipin with phosphatidylglycerol, a lipid that is structurally similar to cardiolipin but does not promote negative membrane curvature in the presence of calcium, prevents the tBid from promoting leakage. The promotion of leakage by tBid is also inhibited by several substances that promote positive membrane curvature, including lysophosphatidylcholine, tritrpticin, a potent antimicrobial peptide, and cyclosporin A, a known inhibitor of cytochrome c release from mitochondria. We directly measured the effect of tBid on membrane curvature by (31)P NMR. We found that tBid promotes the formation of highly curved non-lamellar phases. All of these data are consistent with the hypothesis that tBid promotes negative curvature, and as a result it destabilizes bilayer membranes. Bcl-X(L) inhibits leakage and lipid mixing induced by tBid. Bcl-X(L) is anti-apoptotic. It reduces the promotion of non-bilayer phases by tBid, although by itself Bcl-X(L) is capable of promoting their formation. Bcl-X(L) has little effect on liposomal integrity. Our results suggest that the anti-apoptotic activity of Bcl-X(L) is not a consequence of its interaction with membranes, but rather with other proteins, such as tBid.

The endogenous cannabinoid receptor ligand, anandamide (AEA), is a full agonist of the vanilloid receptor type 1 (VR1) for capsaicin. Here, we demonstrate that the potency and efficacy of AEA at VR1 receptors can be significantly increased by the concomitant activation of protein kinase A (PKA). In human embryonic kidney (HEK) cells over-expressing human VR1, AEA induces a rise in cytosolic Ca(2+) concentration that is mediated by this receptor. The EC(50) for this effect was decreased five-fold in the presence of forskolin (FRSK, 1-5 microM) or the cAMP analogue, 8-Br-cAMP (10-100 microM). The effects of 8-Br-cAMP and FRSK were blocked by a selective PKA inhibitor. The FRSK (10 nM) also potently enhanced the sensory neurone- and VR1-mediated constriction by AEA of isolated guinea-pig bronchi, and this effect was abolished by a PKA inhibitor. In rat dorsal root ganglia slices, AEA-induced release of substance P, an effect mediated by VR1 activation, was enhanced three-fold by FRSK (10 nM). Thus, the ability of AEA to stimulate sensory VR1, with subsequent neuropeptide release, appears to be regulated by the state of activation of PKA. This observation supports the hypothesis that endogenous AEA might stimulate VR1 under certain pathophysiological conditions.