Regulation of human T lymphoblast growth by sensory neuropeptides: augmentation of cholecystokinin-induced inhibition of Molt-4 proliferation by somatostatin and vasoactive intestinal peptide in vitro.

The effects on proliferation of Molt-4 lymphoblasts of cholecystokinin (CCK-8), somatostatin-14 (SS), vasoactive intestinal peptide (VIP) and substance P (SP) were investigated using different combinations of the peptides, peptide analogs and their antagonists. In vitro proliferation of the cells was measured by a colorimetric assay for cell growth and survival. Results indicate that SP and SP (3-11) stimulated, whereas CCK-8, VIP and SS inhibited, proliferation in a dose-dependent manner (P < 0.05). Unsulfated CCK-8 had no effect on growth of Molt-4 lymphoblasts, and a specific antagonist of CCK, at a concentration 10(-6) M, diminished the inhibitory effect of CCK-8 on Molt lymphoblasts (P < 0.05). This suggests that the inhibitory action of CCK-8 was mediated by peripheral-type CCK receptors. SS and VIP, at equimolar concentrations of 10(-6) M, significantly augmented the CCK-8-induced inhibition of Molt-4 lymphoblast proliferation. However, none of the inhibiting neuropeptides suppressed stimulation of Molt-4 lymphoblast proliferation in response to SP. These data suggest a role of sensory neuropeptides including CCK in modulating human T lymphoblast proliferation during neuroendocrine interactions with the immune system.     

Protecting effects of vasoactive intestinal polypeptide on lymphocytes against metal toxicity.

The hormonal neuropeptides calcitonin gene-related peptide (CGRP), cholecystokinin (CCK), neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP), were investigated for a potential protective effect on thymocytes after a toxic dose of nickel sulfate, giving an inhibition of DNA synthesis. There was a statistically significant increase in the synthesis of DNA from the level caused by nickel sulfate, with VIP, 10(-4)-10(-5) mol/l, while the slightly stimulating effects obtained with CGRP, CCK and NPY, were statistically non-significant. This indicates that VIP, at least as pharmacological concentrations, might have protective effects on lymphocytes against metal toxicity.     

Effects of transient forebrain ischemia on peptidergic neurons and astroglial cells: evidence for recovery of peptide immunoreactivities in neocortex and striatum but not hippocampal formation

Summary The effects of transient (30') forebrain ischemia (4 vessel occlusion model) on peptidergic neurons and astroglial cells in various diencephalic and telencephalic areas have been analyzed. The study was performed at various time intervals of reperfusion, i.e. 4 h, 1, 7 and 40 days. Neuropeptide Y (NPY), somatostatin (SRIF), cholecystokinin (CCK), vasoactive intestinal polypeptide (VIP) and arginin-vasopressin (AVP) immunoreactive (IR) neuronal systems and glial fibrillary acidic protein (GFAP)-IR glial cells have been visualized by means of the indirect immunoperoxidase procedure using the avidin-biotin technique. The analysis was performed by means of computer assisted microdensitometry and manual cell counting. At the hippocampal level a huge reduction of neuropeptide (CCK, SRIF, VIP) IR cell bodies was observed, still present 40 days after reperfusion. On the contrary, in the frontoparietal cortex the number of the neuropeptide (CCK, SRIF, VIP, NPY) IR neurons showed a decrease at 4 h, 1 and 7 days after reperfusion followed by a complete recovery at 40 days. A rapid reduction followed by an almost complete recovery (7 days after reperfusion) was also observed at striatal level where SRIF- and NPY-IR neurons were detected. A marked decrease of NPY-IR terminals was observed in the paraventricular and periventricular hypothalamic nuclei and in the paraventricular thalamic nucleus. AVP-IR was markedly reduced in the magnocellular part of the paraventricular nucleus throughout the analyzed period (7 days after reperfusion). GFAP-IR was increased in the hippocampal formation and neostriatum while a not consistent increase was observed at neocortical level. These data point to a differential recovery of peptide-IR and to a different astroglial response in the various brain areas after transient forebrain ischemia. Region-specific factors rather than factors related to neuronal chemical coding seems to play a major role in determining the vulnerability of neuronal populations to transient ischemia.     

Electromyographic studies of neck muscles in the intact cat

Summary Substance P (SP)-, vasoactive intestinal polypeptide (VIP)-, and cholecystokinin (CCK)-like immunoreactive (LI) neurons were found in the superior colliculus (SC) of the rat, and examined to ascertain whether they sent projection fibers to the dorsal lateral geniculate nucleus (LGNd). Immunocytochemical staining with antisera against SP, VIP, and CCK showed that many immunoreactive neuronal cell bodies were located in the superficial layers of the SC, especially in the stratum griseum superficiale. The pattern of distribution of these immunoreactive neuronal cell bodies in the SC was similar to that of neuronal cell bodies which were retrogradely labeled with WGA-HRP (wheat germ agglutinin-horseradish peroxidase conjugate) injected ipsilaterally into the LGNd. On the other hand, SP-, VIP- and CCK-LI axons were seen most densely in the lateral part of the LGNd, especially in the small-celled LGNd zone adjacent to the optic tract, where anterograde labeling was also observed after injection of WGA-HRP ipsilaterally into the superficial layers of the SC. When a lesion was produced by kainic acid injection into the superficial layers of the SC, axons showing SP-, VIP-, or CCK-LI in the LGNd ipsilateral to the lesion were markedly depleted. The results indicate that SC-LGNd projection neurons contain SP, VIP, and/or CCK in the rat.     

Protecting Effects of Vasoactive Intestinal Polypeptide on Lymphocytes Against Metal Toxicity

The hormonal neuropeptides calcitonin gene-related peptide (CGRP), cholecystokinin (CCK), neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP), were investigated for a potential protective effect on thymocytes after a toxic dose of nickel sulfate, giving an inhibition of DNA synthesis. There was a statistically significant increase in the synthesis of DNA from the level caused by nickel sulfate, with VIP, l0^-4-10^-5 mol/l, while the slightly stimulating effects obtained with CGRP, CCK and NPY, were statistically non-significant. This indicates that VIP, at least as pharmacological concentrations, might have protective effects on lymphocytes against metal toxicity.     

Effect of substance P on CCK- or VIP-induced choleresis in anesthetized dogs.

10 anesthetized dogs were provided with acute common bile duct fistulas and the gallbladder was excluded. Hepatic bile output and biliary content of sodium, potassium and amylase were studied. 6 caval infusions were administered of CCK, 0.3 Ivy U.kg-1.min-1, with a superimposed infusion of SP, 20 ng.kg-1.min-1. 7 caval infusions were given of VIP, 50 ng.kg-1.min-1, with a superimposed infusion of SP, 20 ng. kg-1.min-1. CCK increased bile output and biliary content of sodium, potassium and amylase by 78-110%. The corresponding increase induced by VIP was 55-85%. Biliary pH was not influenced. SP abolished the effects of both CCK and VIP. It is suggested that all peptides studied influenced canalicular bile secretion by changing the electrolyte excretion.     

Effect of cholecystokinin octapeptide and vasoactive intestinal polypeptide on adrenocortical secretion in the rat

Intraperitoneal (i.p.) injection of C-terminal octapeptide of cholecystokinin (CCK-8) produced a dose-related increase in plasma corticosterone levels in intact rats, but not in vagotomized ones. Intracerebroventricular (i.c.v.) injection of CCK-8 was ineffective in stimulating the secretion of corticosterone, and in vitro experiment on ACTH release indicated that CCK-8 could not affect pituitary tissue directly. Since i.p. injection of non-sulfated CCK-8 failed to elevate plasma corticosterone levels, sulfated tyrosine residue in the CCK molecule is assumed to be indispensable for the stimulation of visceral organs. On the other hand, vasoactive intestinal polypeptide (VIP) was found to cause a dose-dependent increase in plasma corticosterone levels when administered centrally, but not after i.p. injection. However, VIP could not stimulate the release of ACTH from the pituitary tissue directly. The results suggest that VIP, but not CCK, stimulates the hypothalamic CRF neurons either directly or indirectly.     

Vasoactive intestinal polypeptide increases in areas of the dorsal horn of the spinal cord from which other neuropeptides are depleted following peripheral axotomy

Summary Peripheral nerve section or local capsaicin application produces depletion of substance P and an enzymatic marker, fluoride-resistant acid phosphatase (FRAP), from circumscribed regions of the terminal areas in the spinal cord. We have made use of this phenomenon to map the extent of central termination of subpopulations of primary afferent neurons containing substance P (SP), somatostatin (SOM), cholecystokinin (CCK), vasoactive intestinal polypeptide (VIP) and FRAP in the rat lumbar spinal cord following sciatic nerve section at midthigh level under ether anaesthesia. Between 2 days and 1 year postoperatively, the animals were perfused transcardially and SP, CCK, VIP and SOM were localised in frozen transverse sections of spinal cord segments L1 to S2 and their corresponding ganglia using unlabelled antibody immunohistochemistry. FRAP was localised using a modified Gomori method. SP, SOM, CCK and FRAP were maximally depleted from identical restricted areas of the dorsal horn of the third, fourth and fifth lumbar segments fifteen days after nerve section and remained so for a year. In contrast, VIP staining increased dramatically in the areas from which the other markers were depleted and showed the same time course. Moreover, a large number of neurons in the corresponding ganglia showed positive VIP immunoreactivity after axotomy but were absent from the unoperated side.     

Protecting Effects of Vasoactive Intestinal Polypeptide on Lymphocytes Against Metal Toxicity

Abstract

The hormonal neuropeptides calcitonin gene-related peptide (CGRP), cholecystokinin (CCK), neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP), were investigated for a potential protective effect on thymocytes after a toxic dose of nickel sulfate, giving an inhibition of DNA synthesis. There was a statistically significant increase in the synthesis of DNA from the level caused by nickel sulfate, with VIP, l0^-4-10^-5 mol/l, while the slightly stimulating effects obtained with CGRP, CCK and NPY, were statistically non-significant. This indicates that VIP, at least as pharmacological concentrations, might have protective effects on lymphocytes against metal toxicity.     

大鼠脊髓后角浅层内六种肽类和5-羟色胺的来源及其功能探讨

分别切断大鼠一侧坐骨神经和半横切颈髓上段,用免疫组织化学技术观察了L_(4-6)后角浅层内SP、CCK、SOM、VIP、L-ENK、NT、5-HT等的量的改变。并半横切L_5节段的吻、尾侧,观察了NT在同节段内的含量改变。 1.切断坐骨神经后,术侧L_(4-6)后角浅层的坐骨神经占位区内SP、CCK、SOM、VIP有不同程度的脱失,SP、CCK最明显。结合文献,作者认为后根节中SP、CCK、SOM、VIP阳性神经元外周突部分分布于外周躯体神经。 2.半横切颈髓后,术侧L_(4-5)后角浅层的5-HT阳性反应物基本消失,而L_6后角浅层内有少量存留。CCK、L-ENK阳性反庆物在L_(4-6)节段背外侧索中明显减少,但后角浅层只有轻微减少。SOM在术侧后角浅层中也似有轻微减少。这些提示脑结构到脊髓后角浅层的下行纤维中除含有5-HT外还含有一些神经肽。 3.L—ENK阳性反应物在切断坐骨神经后轻度增高;SOM无论在切断坐骨神经或半横切劲髓例均变比不大;NT在此两组实验中均无变化,且在L_5节段吻、尾侧半切腰髓后L_5后角浅层内仍无变化。以上提示分布于后角浅层的某些肽类有一部分直接来自脊髓内甚至同节段内的固有神经元。     

Immunohistological studies for gastrointestinal and other hormones in acth-secreting adenomas

Eighty-nine ACTH-secreting pituitary adenomas from patients with Cushing’s disease or Nelson’s syndrome were investigated by immunohistochemical methods for their content of gastrin, cholecystokinin (CCK), vasoactive intestinal peptide (VIP), bombesin, substance P, and ubiquitin as a marker for intercellular fibrils and hyalin and D11 as a marker for adrenocortical tissue. In contrast to in vitro studies reported in the relevant literature, we did not find significantly positive percentages (more than 10% of adenoma cells) for gastrin and CCK. VIP and bombesin were demonstrated in one adenoma. Among the adenomas examined, ubiquitin was found in 15% and D11 in 75%. ACTH was present in 99%, pro-γ-MSH in 21 %, β-endorphin in 13%, enkephalin in 4%, and α-subunit in 11.5%. The significance of the findings is discussed.     

Effect of substance P on CCK- or VIP-induced choleresis in anesthetized dogs

10 anesthetized dogs were provided with acute common bile duct fistulas and the gallbladder was excluded. Hepatic bile output and biliary content of sodium, potassium and amylase were studied. 6 caval infusions were administered of CCK, 0.3 Ivy U-kg^-1 min^-1, with a superimposed infusion of SP, 20 ng kg^-1 min^-1. 7 caval infusions were given of VIP, 50 ng-kg^-1 min^-1, with a superimposed infusion of SP, 20 ng·kg^-1 min^-1. CCK increased bile output and biliary content of sodium, potassium and amylase by 78–110%. The corresponding increase induced by VIP was 55–85%. Biliary pH was not influenced. SP abolished the effects of both CCK and VIP. It is suggested that all peptides studied influenced canalicular bile secretion by changing the electrolyte excretion.     

Ontogeny of vasoactive intestinal peptide gene expression in rat brain

Vasoactive intestinal peptide (VIP) expression was studied during rat brain development using in situ hybridization histochemistry with a 48mer, S³⁵-ATP-labeled probe. First expression of VIP was found in the lateral thalamus at E17, in a region later recognized as the reticular nucleus. At E19, VIP mRNA was also found in the hypothalamus, especially the suprachiasmatic nucleus. The only other prenatal localizations were the cortex and the brainstem. VIP expression continously matured during the first three postnatal weeks, and adultlike patterns were found at P22, when cerebral cortex, ventrolateral and reticular thalamic nuclei, suprachiasmatic nucleus were the regions with most prominent VIP expression. These results demonstrate the relatively late appearance of VIP gene expression in the rat forebrain as compared with peptides like SRIF and CCK, suggesting it does not have a major role in early brain maturation.     

Calbindin-D(28K) cells selectively contact intra-SCN neurons

Calbindin-D(28K)-immunoreactive cells are tightly packed within a discrete region of the caudal aspect of the suprachiasmatic nuclei of hamsters. These cells receive direct retinal input and are Fos-positive in response to a light pulse. Knowledge of their afferent and efferent connections is necessary to understand suprachiasmatic nucleus organization. The first aim of the present study is to identify interconnections between calbindin and other peptidergic cells of the suprachiasmatic nuclei, using epi- and confocal microscopy and intra-suprachiasmatic nucleus tract tracing. The results indicate that essentially all calbindin cells receive numerous appositions from vasoactive intestinal polypeptide (VIP), neuropeptide Y and serotonin fibers and that most receive appositions from gastrin releasing peptide (GRP) and cholecystokinin (CCK) fibers. Reciprocal connections are seen from VIP, GRP and CCK cells but surprisingly, not from dorsomedial vasopressin cells. Injection of biotinylated dextran amine into the suprachiasmatic nucleus indicates that the ventrolateral suprachiasmatic nucleus projects to the entire nucleus, while the dorsal and medial regions of the suprachiasmatic nucleus project densely to most of the nucleus, except to the calbindin region. Analysis of colocalization of the peptides in the calbindin cell region shows that 91% of the substance P cells, 42% of the GRP cells and 60% of the VIP cells in the calbindin subnucleus coexpress calbindin-D(28K).Our results reveal a highly specialized topographical organization of connections among suprachiasmatic nucleus cells.     

Tumor necrosis factor-alpha: is there a continuum of liability between stress, anxiety states and anorexia nervosa?

Since the time of Freud, psychiatry has embraced the proposition that physiological and/or psychological stress precipitates various psychiatric disorders. To this effect, we propose that a continuum of liability obtains between stress, anxiety states and anorexia nervosa--a continuum which is grounded on a cytokine profile common to each of these conditions. For example, the biological response to stress, anxiety states and anorexia nervosa includes the elevation of interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha), and downregulation of interferon-gamma (IFN-gamma). Sustained elevation of IL-1 beta and TNF-alpha dysregulates both somatostatin and insulin secretion, the latter of which influences regional cerebral blood flow (rCBF) and brain energy metabolism. In addition, IL-1 beta and TNF-alpha influence the expression of certain crucial neuropeptides, which are known to be associated with anxiety states and anorexia nervosa. These neuropeptides include: beta-endorphin, cholecystokinin (CCK), neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP). beta-endorphin effects glucose metabolism in the limbic system, CCK increases the release of beta-endorphin from the anterior pituitary, NPY is a powerful anxiolytic that regulates beta-endorphin and insulin, while VIP indirectly regulates the expression of TNF-alpha through the inhibition of interleukin-4 (IL-4).     

ATP介导的嘌呤能信号在阿尔茨海默病相关结肠运动障碍中的作用

目的:探讨ATP介导的嘌呤能信号在阿尔茨海默病(Alzheimer’s disease,AD)相关结肠运动障碍中的作用及其相关的分子机制。方法:(1)临床试验:收集我院20例AD患者进行研究,放射免疫法测定血浆中胃动素(motilin,MTL)、胆囊收缩素(cholecystokinin,CCK)、血管活性肠肽(vasoactive intestinal peptide,VIP)和一氧化氮(nitric oxide,NO)水平;高效液相色谱法(high-performance liquid chromatography,HPLC)检测血浆三磷酸腺苷(adenosine triphosphate,ATP)水平,同时对患者进行神经心理学检查并积分。(2)动物实验:利用AD小鼠进行Morris水迷宫实验,评估空间学习记忆功能;放射免疫法测定血浆中MTL、CCK、VIP和NO水平,HPLC法检测血浆ATP水平;免疫组织化学法检测乙酰胆碱转移酶(choline acetyltransferase,ChAT)、VIP、一氧化氮合酶(nitric oxide synthase,NOS)和ATP合酶的变化;Western blot和免疫组化法检测P2Y受体表达水平的变化。(3)离体实验:离体器官浴槽系统观察P2Y受体激动剂α,β-亚甲基ATP(α,β-methylene ATP,α,β-MeATP)对自发性及电刺激诱导的结肠平滑肌收缩的影响,细胞内微电极技术观察α,β-MeATP对结肠平滑肌细胞膜电位的影响。结果:与对照组比较,AD患者血浆的MTL和CCK水平明显降低(P0.01),NO和ATP水平显著升高(P0.05或P0.01),VIP无明显变化。患者简明精神状态检查积分(MMSE)降低(P0.05),AD评定量表-认知分量表(ADAS-Cog)积分、神经精神问卷(NPI)积分和AD协作研究日常能力量表(ADCS-ADL)积分均明显高于对照组(P0.01)。AD小鼠4~6 d逃逸潜伏期明显延长(P0.05),空间探索能力明显降低(P0.05),AD小鼠血浆中MTL和CCK水平明显降低(P0.01),NO和ATP水平显著升高(P0.05或P0.01),VIP无明显变化,AD小鼠结肠表达ATP合酶的水平明显上调(P0.05),但ChAT、VIP和NOS无明显改变,同时P2Y受体表达水平升高(P0.01)。体外实验表明,α,β-MeATP呈浓度依赖性抑制对照组和AD组小鼠结肠平滑肌自发性收缩(P0.05或P0.01),且这种抑制作用可被Na+通道阻断剂河豚毒素(tetrodotoxin,TTX)逆转(P0.05或P0.01),α,β-MeATP在100μmol/L时对AD小鼠自发性收缩的抑制作用更明显(P0.05),AD小鼠与正常小鼠比较,TTX对100μmol/L的α,β-MeATP的拮抗作用差异也有统计学显著性(P0.05)。在10 Hz电刺激诱导的结肠平滑肌收缩中,α,β-MeATP抑制正常小鼠和AD组小鼠的收缩(P0.05或P0.01),且40μmol/L和100μmol/L时对AD小鼠的抑制作用比正常小鼠明显(P0.05或P0.01)。平滑肌细胞膜电位实验显示,α,β-MeATP不影响结肠平滑肌膜电位(P0.05)。结论:AD患者和AD小鼠血浆中促进胃肠运动的激素MTL和CCK水平降低,抑制胃肠运动的激素NO水平升高,胃肠总体运动功能被抑制;AD小鼠血浆ATP水平升高,同时ATP嘌呤能神经元增加,P2Y受体表达上调;在AD发病中,ATP介导的嘌呤能信号可能通过抑制结肠平滑肌收缩,从而导致结肠运动功能障碍。     

Distribution of peptide- and catecholamine-containing neurons in the gastro-intestinal tract of rat and guinea-pig: immunohistochemical studies with antisera to substance P, vasoactive intestinal polypeptide, enkephalins, somatostatin, gastrin/cholecystokinin, neurotensin and dopamine beta-hydroxylase

The distribution of peptide-containing neurons in the oesophagus, stomach and small and large intestine of the rat and the guinea-pig has been studied with the indirect immunofluorescence technique ofCoons &; Co-workers (1958) using antisera to substance P, vasoactive intestinal polypeptide (VIP), enkephalin, somatostatin, gastrin and neurotensin. (The gastrin antiserum is to the C-terminal portion and consequently reacts also with cholecystokinin (CCK)-like peptides.) For comparison, the noradrenergic innervation was visualized with antiserum to dopamine β-hydroxylase. For improved visualization of peptide-containing cell bodies, a mitotic inhibitor (colchicine or vinblastine) was applied locally on the different parts of the gastro-intestinal tract of several animals.Substance P-, VIP-, enkephalin- and somatostatin-like immunoreactivity was observed in all parts of the gastro-intestinal tract studied. Gastrin/CCK had a more limited distribution, especially in the guinea-pig and neurotensin was seen only in certain regions and layers of the rat gastro-intestinal tract.Immunoreactivity to all peptides except neurotensin was observed both in cell bodies and fibres; immunoreactivity to neurotensin has so far only been seen in nerve fibres. Substance P and enkephalin immunoreactive cells were often numerous in the myenteric plexus, whereas VIP and somatostatin immunoreactive cells were preferentially located in the submucous plexus. Some VIP immunoreactive cells were observed in the lamina propria. Large numbers of especially substance P-, VIP- and enkephalin-containing fibres were often seen in the circular muscle layer and in the two ganglionic plexuses. Substance P immunoreactive fibres formed the densest network in the ganglionic plexuses, whereas VIP immunoreactive fibres constituted the most impressive network in the lamina propria and often extended into the most superficial parts of the mucosa. Enkephalin immunoreactive structures were mainly confined to the circular and longitudinal muscle layers and the myenteric plexus. Somatostatin immunoreactive fibres were mainly found in the ganglionic plexuses.Peptide-containing fibres, particularly these containing substance P and VIP were often seen along blood vessels, but never with such a density as the noradrenergic (dopamine β-hydroxylase immunoreactive) fibres. No somatostatin or neurotensin immunoreactive fibres were observed in relation to clearly identifiable blood vessels.The possible coexistence of two peptides in one neuron was studied. For this part of the study the proximal colon and five antisera, namely substance P, VIP, enkephalin. somatostatin and gastrin/CCK antisera were selected. Evidence was obtained for the occurrence of a somatostatin-like and a gastrin/ CCK-like peptide in the same neurons. This may indicate a common precursor for the two peptides in these particular neurons. Each of the substance P-, VIP- and enkephalin-like peptides. on the other hand, seem to be present in different neuronal populations, which were themselves distinct from the somatostatin-gastrin/CCK immunoreactive neurons. In addition, somatostatin immunoreactive neurons different from the gastrin/CCK immunoreactive ones seem to exist. The gastrin/CCK immunoreactive fibres around blood vessels may represent a further, separate population of fibres, since no somatostatin immunoreactive fibres were seen at this location.The findings indicate the existence of numerous subpopulations of enteric neurons, each characterized by its content of a certain peptide (or peptides). The axons of most of these neurons probably terminate in the wall of the gastro-intestinal tract, but some seem to project to other organs. In addition, some peptide-containing fibres in the gastro-intestinal wall may have an extrinsic origin. The relationship between these peptide-containing neurons and the cholinergic enteric neurons and any of the other non-cholinergic. non-adrenergic inhibitory and excitatory neurons present in the enteric nervous system is not known. It is, however, noteworthy that a somatostatin-like peptide seems to be present in noradrenergic neurons of prevertebral ganglia that project to the intestine. The possibility must be kept in mind that one or more of the peptides in the gut could be localized in neurons that contain other potential transmitters, e.g. acetylcholine.The wide variety of pharmacological actions of these neuronal peptides on smooth muscle and neurons in the gut and on its blood vessels raises the possibility that some of them may be neurotransmitters.     

Parvalbumin,somatostatin and cholecystokinin as chemical markers for specific GABAergic interneuron types in the rat frontal cortex

It remains to be clarified how many classes of GABAergic nonpyramidal cells exist in the cortical circuit. We have divided GABA cells in the rat frontal cortex into 3 groups, based on their firing characteristics: fast-spiking (FS) cells, late-spiking (LS) cells, and non-FS cells. Expression of calcium-binding proteins and peptides could be shown in separate groups of GABA cells in layers II/III and V of the frontal cortex: (1) parvalbumin cells, (2) somatostatin cells, (3) calretinin and/or vasoactive intestinal polypeptide (VIP) cells [partially positive for cholecystokinin (CCK)] and (4) large CCK cells (almost negative for VIP/calretinin). Combining the physiological and chemical properties of morphologically diverse nonpyramidal cells allows division into several groups, including FS basket cells containing parvalbumin, non-FS somatostatin Martinotti cells with ascending axonal arbors, and non-FS large basket cells positive for CCK. These subtypes show characteristic spatial distributions of axon collaterals and the innervation tendency of postsynaptic elements. With synchronized activity induced by cortical excitatory or inhibitory circuits, firing patterns were also found to differ. Subtype-selective occurrence of electrical coupling, finding for potassium channel Kv3.1 proteins, and cholinergic and serotonergic modulation supports our tentative classification. To clarify the functional architecture in the frontal cortex, it is important to reveal the connectional characteristics of GABA cell subtypes and determine whether they are similar to those in other cortical regions.     

Mechanism of cholecystokinin inhibition of lower esophageal sphincter pressure.

The purpose of this study were 1) to quantify the lower esophageal sphincter (LES) response to intravenous cholecystokinin (CCK) in both man and the opossum in vivo, 2) to characterize the interaction of CCK and gastrin on circular muscle of the LES, and 3) to determine the site of action of CCK on LES muscle. In both man and the opossum LES pressure was decreased significantly by either constant intravenous infusion or bolus injection of CCK. In vitro dose-response curves to gastrin I, CCK, and the octapeptide of CCK (OP) demonstrated that both CCK and OP were partial agonists on the LES muscle. Both CCK and OP contract LES muscle at lower threshold doses, but give smaller maximum responses than gastrin I. The maximum response of LES muscle to CCK was antagonized only by atropine and tetrodotoxin, but not by other antagonists, suggesting that CCK contracts LES muscle by acetylcholine release. In vitro studies on LES muscle showed that CCK selectively antagonized the effect of gastrin I, but not other agonists. These studied suggest that CCK reduces LES pressure in vivo by inhibition of the endogenous gastrin effect.