The behavioral effects of AR-R 15849, a novel cholecystokinin agonist with high affinity and selectivity for the CCK-A receptor subtype, were examined. Initially, using an operant feeding paradigm to test for anorectic activity and specificity, acute administration of AR-R 15849 was found to alter the intake and pattern of feeding in a manner similar to prefeeding. Further, AR-R 15849 did not induce compensatory feeding as did CCK-8, and did not affect performance on running rates of responding, or motor activity on a running wheel, as did fenfluramine. In tests for subchronic anorectic activity, daily intraperitoneal injections of AR-R 15849 significantly reduced food intake in fasted rats over a 9-day test period with greater efficacy compared to its nonselective predecessor AR-R 14294 (formerly FPL 14294). The sustained decrease in food intake with AR-R 15849 treatment resulted in a significant reduction in body weight gain over 9 days. Finally, an experiment designed to determine the effect of caloric deprivation and subchronic drug exposure on the overall efficacy of AR-R 15849 indicated that pharmacological tolerance does not develop following subchronic treatment.

The three-dimensional molecular shape analysis-quantitative structure-activity relationship (3D-MSA-QSAR) technique has been applied to develop correlations between the calculated physicochemical properties and the in vitro activities of a series of 3-(acylamino)-5-phenyl-2H-1,4-benzodiazepine cholecystokinin-A (CCK-A) antagonists. 3D-MSA-QSARs were developed for varying subsets of 53 analogs (J. Med. Chem. 1988, 31, 2235-2246). An active conformation is hypothesized for these compounds using the loss in biological activity-loss in conformational stability principle. After placing all compounds in the active conformation and performing pairwise molecular shape analysis, it was determined that not any one analog serves as the best shape reference compound. Nonidentical volumes of allowed receptor space are mapped out by different antagonists. A shape reference compound that consists of selected overlapped structures expands the definition of the accessible receptor space. This type of mutant improves the predicted activity of analogs over the value predicted if only one compound is chosen as the reference. Molecular shape, as represented by common overlap steric volume and nonoverlap steric volume, is the major factor contributing to the affinity of this class of compounds. Intramolecular conformational stability, as measured by the difference in energy of the active conformation and the global minimum energy conformation, is also important. It is further concluded from the 3D-MSA-QSAR models that part of the binding pocket for the 3-amido substituent has a preference for lipophilicity. The method used in this study of fragmenting the antagonist into spheres of varying radii and measuring lipophilicity isolates the substructure with highest probability of interacting with the receptor. Two indicator variables marking the presence of an N-methyl group and an o-fluoro atom on the 5'-phenyl substituent of the benzodiazepine ring structure also contribute significantly to the 3D-MSA-QSAR models. The 3D-MSA-QSAR results have led to the proposal of a 3D pharmacophore model for the benzodiazepine CCK-A antagonists.

The effects of two selective CCK(B) agonists, BC 264 and BC 197, on memory processes were investigated in rats using a recently developed two-trial recognition memory task. Control animals showed recognition memory after a 2 but not a 6 h time interval between the two trials, thus allowing a memory impairing (2 h) or improving (6 h) effect of pharmacological treatments to be measured. Drugs were injected i.p. before the second trial (retrieval phase). This experimental procedure was first studied with scopolamine and DL-amphetamine, for which a significant deficit after a 2 h interval or improvement after a 6 h interval of performance was observed, respectively. The CCK(B) agonist, BC 264, was ineffective after a 2 h time interval, whereas the dose of 0.3 microg/kg significantly enhanced performance after a 6 h inter-trial interval. In contrast, BC 197 (30 microg/kg) produced a significant disruption of performance after a 2 h inter-trial interval but was without effect after a 6 h time interval. The effects of the two CCK(B) agonists were abolished by pretreatment with a selective CCK(B) antagonist, L365,260 but not by a selective CCK(A) antagonist, L364,718. The present results suggest that CCK(B) receptors display functional heterogeneity and that CCK(B) agonists like BC 264 could offer a new perspective for the treatment of attentional and/or memory deficits.

Effects of a new cholecystokinin (CCK)A-receptor antagonist, T-0632 [sodium (S)-1-(2-fluorophenyl)-2, 3-dihydro-3-[(3-isoquinolinylcarbonyl) amino]-6-methoxy-2-oxo-1H-indole-3-propanoate], on caerulein-induced and pancreatic duct ligation-induced pancreatitis models were studied and compared with the CCKA-receptor antagonist loxiglumide and the orally active protease inhibitor camostate, respectively. In rats, orally administered T-0632 potently prevented the caerulein-induced increases in pancreatic digestive enzymes in plasma and suppressed the histological changes in the pancreas. The estimated ED50 values of T-0632 and loxiglumide were 0.0092 and 8.9 mg/kg, respectively. In dogs, T-0632 (0.1, 1 mg/kg, i.d.) prevented the caerulein-induced increase in plasma amylase activity in a dose-dependent manner. Loxiglumide (100 mg/kg, i.d.) did not show any preventive effects. In pancreatic duct ligation (6 hr)-induced pancreatitis of the rat, T-0632 (0.001-0.1 mg/kg, p.o.) partially prevented both the increase in plasma amylase activity and the histological changes in the pancreas, whereas camostate (10, 100 mg/kg, p.o.) did not show any preventive effects. In pancreatic duct ligation (3 hr)-induced pancreatitis, caerulein injection (1 microgram/kg, s.c.) caused a further increase in plasma amylase activity, and T-0632 (0.01, 0.1 mg/kg, p.o.) dose-dependently decreased the aggravation by caerulein. We conclude that T-0632 showed preventive effects on all of these pancreatitis models by oral or intraduodenal administration. These results suggest that CCK plays an important role in progression and aggravation of acute pancreatitis, and T-0632 may have a therapeutic value in these disease states.

After the injection of CCKAcc. of rats DA, DOPAC HVA contents were determined from punches of the anterior and posterior N. Acc. and VTA. CCKAcc. and these responses were inhibited by the CCK-A antagonist devazepide. Five min after treatment, DA, DOPAC and HVA were increased in the N. Acc.shell and 10 min later they were decreased in the N. Acc.core. These data suggest that in these regions CCKA from the core on the transmission of motor information and favor that of DA from the shell on emotional-like responses.

The carboxyterminal octapeptide of cholecystokinin (CCK-8) coexists with dopamine (DA) in mesolimbic neurons of the ventral tegmental area (VTA). In the present study, in vivo microdialysis in freely moving rats was used to assess the relative effects of sulfated CCK-8 (CCK-8S), unsulfated CCK-8 (CCK-8US) and CCK tetrapeptide (CCK-4), focally injected into the VTA, on DA overflow in two mesolimbic DA/CCK-8S terminal regions, the nucleus accumbens and the amygdala. Consistent with electrophysiological findings, microinjection of CCK-8S, but not CCK-8US or CCK-4, elicited increases in DA overflow in both terminal regions. In the absence of anatomical evidence of CCK-containing fibers in the VTA region, it seems reasonable to conclude that the modulation of terminal DA overflow by CCK-8S through actions at the somatodendritic region represents a form of autoregulation of these cells. Whereas CCK-8US and CCK-4 are preferential CCK-B receptor agonists, CCK-8S binds non-selectively to CCK-A and CCK-B receptors. Thus, these results implicate CCK-A receptors in the stimulatory effects of CCK-8S on VTA DA neurons.

BACKGROUND

Both secretin and cholecystokinin (CCK) inhibit gastric acid secretion. However, their mode of action has yet to be determined. A newly developed primary culture of human antral epithelial cells has been used to examine the effect of secretin and cholecystokinin on somatostatin release.

METHODS

Normal human antral epithelial cell cultures enriched for D cells were maintained in culture for 2 days before release studies.

RESULTS

Native human secretin at 10(-8) mol/L stimulated somatostatin release threefold. Porcine secretin and the secretin analogs, Tyr10 human secretin, Tyr13 porcine secretin, and Tyr10,13 porcine secretin were equipotent to native human secretin. CCK stimulated somatostatin release with the greatest response (eight times basal) at 10(-7) mol/L. The response to CCK was inhibited in a competitive manner by the addition of the benzodiazepine analog, MK-329. Addition of secretin in the presence of 10(-8) mol/L CCK resulted in a potentiation of somatostatin release, with the greatest response at 10(6) mol/L secretin, resulting in a 12-fold increase above basal.

CONCLUSIONS

The stimulation observed after the addition of CCK was the result of activation of the CCK-A receptor subtype. The secretin receptor resembles that of the pancreatic D cells and acts through increasing intracellular cyclic adenosine monophosphate levels. Finally, these data indicate that the inhibitory action of CCK and secretin on gastric acid secretion may result from a synergistic action on antral D cells to release somatostatin, which in turn decreases antral gastrin release.

The successful design of peptoid CCK-B receptor antagonists using rational approaches suggested that it might be feasible to develop similar non-peptide small molecule agonists with potential therapeutic applications. We now report the characterization of such a compound with full agonist activity at CCK-A receptors on rat exocrine pancreatic acinar cells. The compound, PD149164, stimulated a similar maximal response to CCKCCKCCK-A antagonist L-364,718. Interestingly, the enantiomer of PD149164, PD151932, was a CCK-A antagonist and blocked PD149164 stimulated effects on the exocrine pancreas. The data indicate that it is possible to develop both agonist and antagonist activities in enantiomers of small non-peptide molecules.

1. The effects on dorsal raphe neurones of the peptides bombesin, gastrin-releasing peptide and neuromedin B were studied using intracellular recording techniques from slices of rat brain maintained in vitro. The peptides were added to the solutions perfusing the slices. 2. The peptides bombesin, gastrin-releasing peptide and neuromedin B depolarized neurones in the dorsal raphe nucleus. The same neurones were depolarized by phenylephrine and hyperpolarized by 5-hydroxytryptamine (5-HT) but were insensitive to sulphated cholecystokinin octapeptide (CCK). 3. The responses to the peptides were not blocked by CCKA, CCKB and alpha 1-adrenoreceptor antagonists. 4. The response to the peptides persisted in the presence of tetrodotoxin (TTX) and low-calcium, high-magnesium-containing artificial cerebrospinal fluid (ACSF). 5. Under voltage clamp conditions the peptides caused a decrease in membrane conductance accompanied by an inward current. The reversal potential for the event was the same as that for 5-HT. 6. The results of the present study demonstrate that bombesin and the structurally related peptides gastrin-releasing peptide (GRP) and neuromedin B depolarized a subpopulation of raphe 5-HT neurones by acting on a postsynaptically located receptor linked to potassium channels.

Intracerebroventricular administration of SMS 201-995 (5 micrograms/rat), a somatostatin analogue, induced barrel rotation in rats. Pretreatment with ceruletide (40 micrograms/100 g b. wt., IP) 3 days or 7 days prior to the injection of SMS 201-995 significantly inhibited the response rate of barrel rotation induced by SMS 201-995, but not that induced by arginine-vasopressin (1 microgram/rat, ICV). The suppressive effect of ceruletide on barrel rotation could be partially countered by MK-329, a selective peripheral CCK (CCK-A) receptor antagonist. Desulfated cerulein did not affect the barrel rotation induced by SMS 201-995. These findings suggest that ceruletide specifically suppresses the barrel rotation evoked by SMS 201-995 in a long-lasting manner possibly acting through CCK-A receptor.

Prior exposure of isolated perifused rat islets to the sulfated gut hormone cholecystokinin-8 (CCK-8S) dramatically increased their insulin secretory response to 7.5 mM glucose, 10 mM arginine, and 10 mM alpha-ketoisocaproate. In the case of glucose, the heightened secretory response was still apparent 60-80 min after CCK-8S removal from the perifusion medium. Prior exposure of perifused islets to arginine (10 mM), tolbutamide (25 microM), or forskolin (1.0 microM) did not sensitize them to 7.5 mM glucose. CCK-8S exposure increased 3H efflux from islets prelabeled with [3H]inositol, and the increase in 3H efflux was sustained after CCK-8S removal from the perifusion medium. The duration of this increase in 3H efflux paralleled the temporal characteristics of this sensitization process and was significantly attenuated by 25 microM asperlicin, a competitive antagonist of CCK binding to its membrane receptor. Arginine, tolbutamide, or forskolin treatment of islets did not increase 3H efflux from [3H]inositol-prelabeled islets. The results suggest that the turnover of membrane phosphoinositides induced by CCK-8S is largely responsible for this heightened state of secretory responsiveness to various stimulants. Second-messenger molecules generated during phosphoinositide turnover may be responsible for the phenomenon of sensitization displayed by islet tissue to CCK-8S addition.

Cocaine- and amphetamine-regulated transcript (CART) peptide is a recently described neuropeptide that has been localized to areas of the central and peripheral nervous systems. CART has been shown to be involved in feeding behavior when injected centrally, however, its effects upon peripheral tissues have not been studied. This report describes the effects of CART peptide on rat pancreatic exocrine secretion. Infusion of CART peptide caused four-fold increases in amylase secretion from anesthetized rats that had been fashioned with a bile-pancreatic duct cannula. CART peptide-induced increases in pancreatic secretion appear to involve pathways that are sensitive to both acetylcholine (ACh) and cholecystokinin (CCK) since pre-treatment with atropine (ACh receptor antagonist) or L-364,718 (CCK-A receptor antagonist) inhibited the effects of CART peptide on amylase secretion. Pre-treatment with a combination of atropine and L-364,718 abolished the effects of CART peptide. When isolated rat pancreatic acini were exposed to varying doses of CART peptide, no increase in amylase secretion was observed. The results of the present study suggest that CART peptide has stimulatory effects upon pancreatic exocrine secretion. CART peptide-induced increases in pancreatic secretion appear to be indirectly mediated as no direct effect upon pancreatic acini was shown. CART peptide likely acts upon either peripheral or central regulators of pancreatic secretory function that are distant from the acinar unit.

1. The rat CCK(A) and CCK(B) receptors were stably expressed in Chinese hamster ovary (CHO-09) cells in order to compare modes of signal transduction and effects of protein kinase C (PKC) thereupon. 2. Spectrofluorophotometry of Fura-2-loaded cells revealed that both receptors retained their pharmacological characteristics following expression in CHO cells. Sulphated cholecystokinin-(26-33)-peptide amide (CCK-8-S) increased the cytosolic Ca2+ concentration ([Ca2+]i) in CCK(A) cells, measured as an increase in Fura-2 fluorescence emission ratio, 1000 fold more potently than its non-sulphated form (CCK-8-NS) (EC50 values of 0.19 nM and 0.18 microM, respectively). By contrast, CCK-8-S and CCK-8-NS were equally potent in CCK(B) cells (EC50 values of 0.86 nM and 1.18 nM, respectively). The CCK(A) receptor agonist JMV-180 increased [Ca2+]i only in CCK(A) cells. Likewise, pentagastrin increased [Ca2+]i only in CCK(B) cells. Finally, CCK-8-S-induced Ca2+ signalling through the CCK(A) receptor was most potently inhibited by the CCK(A) receptor antagonist L364,718, whereas the CCK(B) receptor antagonist L365,260 was more potent in CCK(B) cells. 3. Receptor-mediated activation of adenylyl cyclase was measured in the presence of the inhibitor of cyclic nucleotide phosphodiesterase activity, 3-isobutyl-1-methylxanthine. CCK-8-S and, to a lesser extent, CCK-8-NS, but not JMV-180 or pentagastrin, stimulated the accumulation of cyclicAMP in CCK(A) cells. By contrast, none of these agonists increased cyclicAMP in CCK(B) cells. 4. Short-term (3 min) pretreatment with the PKC activator 12-O-tetradecanoylphorbol 13-acetate (TPA) evoked a rightward shift of the dose-response curve for the Ca2+ mobilizing effect of CCK-8-S in both cell lines. In addition, short-term TPA pretreatment markedly reduced CCK-8-S-induced cyclicAMP accumulation in CCK(A) cells. In both cases, the inhibitory effect of TPA was abolished by the PKC inhibitors, GF-109203X and staurosporine, whereas no inhibition was observed with the inactive phorbol ester, 4-alpha-phorbol 12-myristate 13-acetate. 5. During prolonged TPA treatment, the cells gradually recovered from phorbol ester inhibition and in the case of CCK-8-S-induced Ca2+ mobilization complete recovery was achieved after 24 h of TPA treatment. Western blot analysis revealed that this recovery was paralleled by down-regulation of PKC-alpha, suggesting the involvement of this PKC isotype in the inhibitory action of TPA. 6. This study demonstrates that following expression in CHO cells (i) both CCK(A) and CCK(B) receptors are coupled to Ca2+ mobilization, (ii) only CCK(A) receptors are coupled to cyclicAMP formation and (iii) with both receptors signalling is inhibited by PKC.

Our recent study demonstrated that by activating CCK-A receptors, CCK-8 excites substantia nigra (SN) dopaminergic (DA) neurons via increasing a non-selective cationic conductance. In the present study, we further studied the molecular mechanism by which CCK-8 induces cationic currents in SN DA neurons. CCK-8-evoked inward currents were inhibited by the intracellular perfusion of GDP-beta-S (1 mM). In DA neurons internally perfused with GTP-gamma-S (0.5 mM), the inward currents produced by CCK-8 became irreversible. Pretreating DA neurons with 500 ng/ml pertussis toxin (PTX) did not significantly affect the ability of CCK-8 to induce cationic currents. Intracellular application of heparin (2 mg/ml), an inositol 1,4,5-trisphosphate (InsP3) receptor antagonist, and buffering intracellular calcium with the Ca(2+)-chelator BAPTA (10 mM) suppressed CCK-8-evoked cationic currents. Dialyzing DA neurons with protein kinase C (PKC) inhibitors, staurosporine and PKC(19-31), failed to prevent CCK-8 from generating cationic currents. It is concluded that PTX-insensitive G-proteins mediate CCK-8-induced enhancement of cationic conductance of SN DA neurons. The coupling mechanism via G-proteins is likely to involve the generation of InsP3, and subsequent InsP3-evoked Ca2+ release from the intracellular store results in activating the non-selective cationic conductance.

Fat has been described to both accelerate and slow intestinal transit. We hypothesized that the fat-induced jejunal brake depends on the combined accelerating effect of CCK and the slowing effect of an opioid pathway. Using a multifistulated model, intestinal transit was measured in four dogs, while 60 mM oleate was delivered into the proximal gut with either 0 or 6 mg naloxone, and 0.1 mg/kg devazepide (a peripheral CCK-A-receptor antagonist) administered intraluminally and intravenously, respectively. In a second study, intestinal transit was measured in seven dogs, while naloxone was delivered intraluminally at 0-, 3-, 6-, or 12-mg doses. Compared to the jejunal brake (marker recovery of 50.1 +/- 2.6%), intestinal transit was slowed by the CCK-A antagonist (36.4 +/- 8.3%; P < 0.05) and accelerated by naloxone (82.0 +/- 6.8%; P < 0.05). The accelerating effect of CCK occurred early in the transit response, while the dose-dependent effect (P < 0.05) of naloxone occurred later. We conclude that fat-induced jejunal brake depends on the early accelerating effect of CCK and the later slowing effect of a naloxone-sensitive opioid pathway.

A study on the biology of 'panic disorder,' which I have classified under the category of 'anxiety disorder,' made progress recently. In a genetic study, the hereditary of panic disorder was checked by a 'linkage and twins' study, and the anticipation of panic disorder was recognized as being the same as that which is also found in the psychiatric conditions known as schizophrenia and manic depression. A panic disorder patient regards the anxious sign of a model as ruinous, and this weakness in recognition has been duly noted. Therefore, I studied a patient showing a continuance state of 'hyper-sensitivity,' and compared this to a patient showing a 'sleep disorder.' Noradrenaline plays an important role in anxiety as suppression of the locus ceruleus (LN), the major NE-containing nucleus of the noradrenaline nervous system, brings on a calming effect. Yohimbine, however, which is an alpha 2 antagonist, is found to induce panic attacks. The fact that selective serotonin reuptake inhibitor (SSRI) suppresses panic attacks suggests that serotonin is connected with panic disorders. It is also thought that the 'raphe nucleus' is the site of origin of the serotonin nervous system, which participates in the control of anxiety. This suggests the participation of a gamma-aminobutyric acid (GABA) nervous system in which the administration of benzodiazepine at a high potency would be an effective agent against panic disorder. Cholecystokinin (CCK) is also suggested to have a connection with panic disorder as CCK-4 causes panic attacks. There has been no CCK antagonist found effective for an object- or time-oriented panic disorder at the present. It is thought that corticotropin-releasing factor (CRF) is released during a panic attack. The development of a new CRF receptor antagonist is needed. In addition to the studies on the neurotransmitters of the traditional type, such as noradrenaline, serotonin and GABA, studies on the neuropeptides, such as CCK and CRF have become important for future consideration. Understanding this, image studies such as MRI, SPECT, fMRI and PET have become highly desirable.

Cholecystokinin (CCK), a hormone secreted from endocrine cells of the small intestine, participates in the control of motility and secretion in the gastrointestinal tract, and in the control of food intake. At least some of the effects of CCK on intestinal function appear to be mediated via activation of intrinsic neurons in the myenteric plexus. However, the distribution of CCK-responsive enteric neurons within the rat small intestine is not known. Neither has the role of CCK-A receptors in the activation of rat myenteric neurons been investigated. Therefore, to determine the distribution of CCK-responsive neurons in the small intestinal myenteric plexus we utilized immunohistochemical detection of Fos, the protein product of the immediate early gene c-fos, to identify neurons that were activated by exogenous CCK. We also monitored Fos expression in the dorsal hindbrain, and examined CCK-induced Fos expression in the presence or absence of a receptor antagonist for the type-A CCK receptor. We found that CCK significantly increased Fos expression in the hindbrain and in myenteric neurons of the duodenum and jejunum, but not the ileum. Neuronal Fos responsiveness in both brain and myenteric neurons was mediated by CCK-A receptors, as CCK-induced Fos expression was eliminated in rats pretreated with a CCK-A receptor antagonist. We conclude that CCK activates small intestinal myenteric neurons, via CCK-A receptors. Activation of these intrinsic intestinal neurons may participate in reflexes and behaviors that are mediated by CCK.

The vasoactive effects of cholecystokinin-octapeptide (CCK-OP), pentagastrin, synthetic secretin, glucagon, and acetylcholine were assessed in the intestinal circulation of the dog. In pharmacologic doses of glucagon, CCK-OP, and, to a lesser degree, pentagastrin significantly increased blood flow and oxygen consumption. Atropine blocked the vasodilator effects of CCK-OP, pentagastrin, and acetylcholine but did not block those of glucagon. Neither the alpha-adrenergic blocker, phenoxybenzamine, nor the beta-adrenergic blocker, propranolol, blocked the vasodilator response to pentagastrin. Synthetic secretin had no significant effect on either blood flow or oxygen consumption in the intestinal segment. The vasodilator response to CCK-OP and pentagastrin appears to be mediated specifically through cholinergic receptors.

BACKGROUND

One of the early events leading to alcoholic pancreatitis seems to be the effect of ethanol on stimulus-secretion coupling. This study examines ethanol-induced modifications of filamentous actin (F-actin) content and localization in acini, the resulting alpha-amylase secretion and the role of protein kinase C (PKC) activity in these processes.

METHODS

Freshly isolated acini were treated with different concentrations of ethanol or cholecystokinin octapeptide (CCK-8) for different periods. F-actin was localized by confocal laser scanning microscopy; its quantity was determined fluorometrically, and the alpha-amylase secretion was measured.

RESULTS

Ethanol caused F-actin reorganization resembling the effects of supramaximal CCK-8 stimulation and of direct PKC activation by phorbol-12-myristate-13-acetate. The polyphasic time course of the F-actin content also resembled that under supramaximal CCK-8 stimulation and was counteracted by inhibition of PKC. The PKC inhibitor bisindolylmaleimide I did not increase the ethanol- induced alpha-amylase secretion, but the suboptimally CCK-8-stimulated secretion via high-affinity receptors.

CONCLUSIONS

Ethanol, like supramaximal CCK-8 concentrations, inhibits acinar secretion by reorganization of the actin cytoskeleton via PKC activation. This effect is suggested to be mediated by low-affinity CCK-A receptors. Together with the ethanol-induced stimulation of early steps of stimulus-secretion coupling, this may be a pancreas-damaging mechanism resembling that in experimental hyperstimulation pancreatitis.

AIM:To study the antagonism of cholecystokinin octapeptide (CCK-8) against the effect of morphine and its mechanism.METHODS:The method of simultaneously recording the electrical and mechanical activities of rat duodenum in vitro was adopted.RESULTS:Acetylcholine (ACh) could increase the amplitude and the number of the spike potential (SPA and SPN of rat duodenum in vitro, followed by the increase of the duodenal contraction amplitudes (CA), showing a positive correlation. Morphine, on the contrary, inhibited the potentiation of ACh, showing a negative correlation. CCK-8 could antagonize the effects of morphine, i.e. th SPA and SPN were increased again, followed by the increase of CA. On the basis of the above, CCK-A receptor antagonist Devazepide could reverse the antagonism of CCK-8 to the effect of morphine.CONCLUSION:CCK-8 could antagonize the effect of morphine which inhibited the potentiation of ACh on the duodenal activities in vitro.Furthermore, it was inferred that the antagonistic effect of CCK-8 on morphine was mainly mediated by CCK-A receptor.

BACKGROUND

We devised a comfort care kit (CCK) consisting of nonoral and nonparenteral rescue medications for caregivers to use at home for symptom control in imminently dying patients who have lost their ability to swallow. The aim of this study was to evaluate the feasibility of the CCK from the perspective of bereaved caregivers.

METHODS

CCKs were handed out to caregivers for patients who were entered into the care for the dying pathway (CDP). Each CCK includes morphine and haloperidol ampoules, lorazepam tablets, atropine drops, and paracetamol suppositories given either through sublingual or rectal route. We conducted a telephone survey of bereaved caregivers to assess CCK's feasibility (proportion of use), pattern of use, perceived benefits and challenges, and need to transfer to emergency department at the end of life.

RESULTS

Forty-nine caregivers completed the survey. Thirty-three (67%) reported that they used the CCK. A majority (76%) only used one medication from the kit. Atropine drops were the most commonly used, followed by morphine and paracetamol. All family members reported that the CCK was easy to use and 98% found it to be effective for symptom management. All except one patient died at home.

CONCLUSIONS

The CCK was feasible and perceived to be effective for symptom control and easy to use. Further research is necessary to optimize the use of this kit and to document related outcomes.

A cholecystokinin (CCK) precursor cDNA of 782 bp was identified from goldfish brain. The open reading frame (369 bp) encodes the 123 amino acid precursor which contains mono- and di-basic amino acid endoproteolytic cleavage, C-terminal alpha-amidation and tyrosyl sulfation sites. Expression studies revealed the presence of preproCCK mRNA in the gastrointestinal tract, pituitary and a wide range of brain areas from the olfactory bulbs to the posterior brain region. We have also confirmed the presence of CCK mRNA in the posterior ventrolateral hypothalamus by in situ hybridization, supporting a role of CCK in feeding behavior and regulation of pituitary hormone secretion.

To prevent the blood-borne interference and reflex actions via neighboring organs and the central nervous system, the study was conducted in an in vitro isolated stomach-gastric vagus nerve preparation obtained from overnight-fasted, urethan-anesthetized rats. Afferent unit action potentials were recorded from the gastric branch of the vagus nerve. The left gastric artery was catheterized for intra-arterial injection. In vitro we found that 1) 55/70 gastric vagal afferents (GVAs) were polymodal, responding to CCK-8 and mechanical stimuli, 13 were mechanoreceptive, and 2 were CCK-responsive; 2) sequential or randomized intra-arterial injections of CCK-8 (0.1-200 pmol) dose-dependently increased firing rate and reached the peak rate at 100 pmol; 3) the action was suppressed by CCK-A (Devazepide) but not by CCK-B (L-365,260) receptor antagonist; 4) neither antagonist blocked the mechanosensitivity of GVA fibers. These results are consistent with corresponding in vivo well-documented findings. Histological data indicate that the layered structure of the stomach wall was preserved in vitro for 6-8 h. Based on these results, it seems reasonable to use the in vitro preparation for conducting a study that is usually difficult to be performed in vivo. For instance, because there was no blood supply in vitro, the composition of the interstitial fluid, i.e., the ambient nerve terminals, can be better controlled and influenced by intra-arterial injection of a defined solution. Here we report that acutely changing the ambient CCK level by a conditioning stimulus (a preceding intra-arterial injection of increasing doses of CCK-8) reduced the CCK sensitivity of GVA terminals to a subsequent test stimulus (a constant dose of CCK-8 intra-arterial injection).

The brain has been traditionally viewed as an immunologically privileged site. However, recent findings suggest that the brain is in fact equipped with its own immune circuitry. Astrocytes and microglia have been considered the most likely candidates to assume the role of intracerebral antigen presenting cells (APC). Using the techniques of immunofluorescence cytochemistry and flow cytometric analysis, we observed that vasoactive intestinal polypeptide (VIP) can significantly inhibit gamma-interferon (IFN-gamma)-induced Ia expression on astrocytes derived from newborn Lewis rats. Further, we analyzed a number of neuropeptides and transmitters for their ability to exert a similar inhibitory modulation on IFN-gamma induced Ia expression or for the ability to induce or augment Ia expression on rat astrocytes. Our results showed that only norepinephrine (NE), a major brain neurotransmitter, and VIP, a ubiquitous brain peptide, have the ability to inhibit Ia expression on Lewis rat astrocyte cultures. Alternately, we report that cholecystokinin (CCK), a brain/gut peptide, has the ability to induce Ia on about 5-10% of the cells analyzed. These findings suggest that endogenous brain substances have the ability to modulate intracerebral immune responses by regulating the expression of Ia on astrocytes.