Effects of homeopathic preparations on the liver in rats with acute and chronic toxic hepatitis.

Ultralow doses of antibodies to phenobarbital and their mixture (1:1) with ultralow doses of antibodies to cholecystokinin reduced the severity of structural and metabolic disturbances in the liver of rats with acute CCl4-induced hepatitis. The mixture of antibodies had no effect on the course of CCl4-induced hepatitis.

Potential role of cholecystokinin in the development of acute pancreatitis.

Evidence based on animal studies suggests that cholecystokinin (CCK) is involved in the induction and development of acute experimental pancreatitis. However, the results obtained with CCK or CCKA receptor antagonists in different species (rats, mice) and different models of acute pancreatitis (cerulein pancreatitis, hemorrhagic pancreatitis induced by choline-deficient, ethionine-supplemented diet, arginine-induced pancreatitis, sodium taurocholate-induced pancreatitis) produced variable results. The route of administration, the specificity and potency of compounds and the design of the study are predictive for the outcome. Based on the available information, CCK appears to play a contributory role in the development of acute experimental pancreatitis in mice and rats. No conclusions can be drawn from these results with respect to the human disease.

Neurochemical features and synaptic connections of large physiologically-identified GABAergic cells in the rat frontal cortex.

Physiological and morphological properties of large non-pyramidal cells immunoreactive for cholecystokinin, parvalbumin or somatostatin were investigated in vitro in the frontal cortex of 18-22-day-old rats. These three peptides were expressed in separate populations including large cells. Cholecystokinin cells and parvalbumin cells made boutons apposed to other cell bodies, but differed in their firing patterns in response to depolarizing current pulses. Parvalbumin cells belonged to fast-spiking cells. Parvalbumin fast-spiking cells also included chandelier cells. In contrast, cholecystokinin cells were found to be regular-spiking non-pyramidal cells or burst-spiking non-pyramidal cells with bursting activity from hyperpolarized potentials (two or more spikes on slow depolarizing humps). Large somatostatin cells belonged to the regular-spiking non-pyramidal category and featured wide or ascending axonal arbors (wide arbor cells and Martinotti cells) which did not seem to be apposed to the somata so frequently as large cholecystokinin and parvalbumin cells. For electron microscopic observations, another population of eight immunohistochemically-uncharacterized non-pyramidal cells were selected: (i) five fast spiking cells including one chandelier cell which are supposed to contain parvalbumin, and (ii) three large regular-spiking non-pyramidal cells with terminals apposed to somata, which are not considered to include somatostatin cells, but some of which may belong to cholecystokinin cells. The fast-spiking cells other than a chandelier cell and the large regular-spiking non-pyramidal cells made GABA-positive synapses on somata (4% and 12% of the synapses in two small to medium fast-spiking cells, 22% and 35% of the synapses in two large fast-spiking cells, and 10%, 18% and 37% of the synapses in three large regular-spiking non-pyramidal cells). A few terminals of the fast-spiking and regular-spiking non-pyramidal cells innervated GABAergic cells. About 30% of the fast-spiking cell terminals innervated spines, but few of the regular-spiking non-pyramidal cell terminals did. A fast-spiking chandelier cell made GABA-positive synapses on GABA-negative axon initial segments. These results suggest that large GABAergic cells are heterogeneous in neuroactive substances, firing patterns and synaptic connections, and that cortical cells receive heterogeneous GABAergic somatic inputs.

Immunoreactivity for GAD and three peptides in somatosensory cortex and thalamus of the raccoon.

Immunocytochemical methods were used to determine the distributions of glutamic acid decarboxylase (GAD), vasoactive intestinal polypeptide (VIP), cholecystokinin (CCK), and somatostatin (SOM) in the primary somatosensory cortex and somatosensory thalamus of adult raccoons. The cortex showed extensive immunoreactivity for GAD, revealing a large population of GABAergic neurons. GAD-labeled cells were numerous in all cortical layers, but were most concentrated in laminae II-IV. The cells were nonpyramidal and of varying morphology, typically with somata of small or medium size. GAD-immunoreactive puncta, presumably synaptic terminals, were widespread and often appeared to end on both GAD-negative and GAD-positive neurons. Immunoreactivity for the peptides was much less extensive than that for GAD, with the number of labeled neurons for VIP > CCK > SOM. Peptidergic cells were preferentially located in the upper and middle cortical layers, especially laminae II and III. The cells were nonpyramidal, often bitufted or bipolar in morphology, and small to medium in size. Their processes formed diffuse plexuses of fibers with terminal-like varicosities that occasionally surrounded nonpeptidergic neurons. The thalamus showed a clearly differentiated pattern of immunoreactivity for GAD, but little or no labeling for the three peptides. Nuclei adjoining the ventral posterior lateral (VPL)/ventral posterior medial (VPM) complex--including the reticular nucleus--contained many GAD-positive neurons and fibers. In contrast, the VPL and VPM nuclei displayed considerably less GAD immunoreactivity, somewhat surprising given the raccoon's highly developed somatosensory system. However, the ventral posterior inferior (VPI) nucleus revealed rather dense GAD labeling, perhaps related to a specialized role in sensory information processing. Thus, the primary somatosensory cortex of the raccoon showed patterns of immunoreactivity for GAD and peptides that were similar to those of other species; the somatosensory thalamus revealed a distinctive profile of GAD immunoreactivity, with labeling that was light to moderate in the VPL/VPM complex and relatively extensive in VPL.

Distribution of cholecystokinin-like immunoreactivity within the stomatogastric nervous systems of four species of decapod crustacea.

The distribution of cholecystokinin-like immunoreactivity was studied in the stomatogastric nervous systems, pericardial organs, and haemolymph of four species of decapod crustacea, by using immunocytochemical and radioimmunoassay techniques. Whereas cholecystokinin-like immunoreactivity was found within the stomatogastric nervous systems of all four species, its distribution in each is unique. Two species (Panulirus interruptus and Homarus americanus) have cholecystokinin-like immunoreactivity within fibers and neuropil of the stomatogastric ganglion (STG); two other species (Cancer antenarius and Procambarus clarkii) do not. Further, the cholecystokinin-like immunoreactivity within the STGs of Panulirus and Homarus arise from distinct structures; from a projection of anterior ganglia in Panulirus, and from somata within the posterior motor nerves in Homarus. The staining in the other ganglia of the stomatogastric nervous system also shows some interspecies variability, although it appears to be more highly conserved than staining within the STG. These differences in staining were confirmed by measuring the amount of CCK-like peptide present in tissue extracts of ganglia by radioimmunoassay. In contrast to the variable staining within the STG, all four species have cholecystokinin-like immunoreactivity within the neurosecretory pericardial organs and thoracic segmental nerves. This cholecystokinin-like immunoreactivity is contained within fibers and within varicosities that coat the surface of these structures. The location of this staining and the presence of detectible levels of CCK-like peptide in the haemolymph suggests that CCK-like peptides in decapod crustacea may be utilized as neurohormones.

Cholecystokinin innervation of monkey prefrontal cortex: an immunohistochemical study.

Knowledge of the circuitry of chemically identified systems in primate prefrontal cortex is limited. Although cholecystokinin is very abundant in prefrontal cortex (Geola et al.: Journal of Clinical Endocrinology and Metabolism 53(2):270-275, 1981; Taquet et al.: Neuroscience 27(3):871-883, 1988), the organization of cholecystokinin-containing structures in primate prefrontal cortex has not been investigated. Using immunohistochemical and retrograde transport techniques, we characterized the cholecystokinin innervation of prefrontal cortex in macaque monkeys. The use of two antibodies directed against different portions of the cholecystokinin molecule revealed that distinct forms of the molecule were differentially localized in the same cortical neurons. These small, nonpyramidal cholecystokinin-positive neurons had a variety of somal morphologies and the density of labeled cells did not differ among cytoarchitectonic regions. Labeled neurons had a distinctive laminar distribution with the greatest density of cells present in layers II-superficial III. Labeled fibers also had a distinctive laminar pattern of distribution that differed from that of the immunoreactive neurons. In granular prefrontal cortex, terminal fields were evident in layers II, IV, and VI, with the greatest density in layer VI. Agranular area 24 exhibited a bilaminar pattern of immunoreactivity with a band in layer II and a very dense terminal field in layers V-VI. A high density of cholecystokinin-binding sites has been found in layers III-IV of prefrontal cortex and other association areas in the monkey; this finding has been attributed to possible cholecystokinin-containing afferents from the thalamus (Kritzer et al.: Journal of Comparative Neurology 263:418-435, 1987). The mediodorsal nucleus of the thalamus is known to be a source of afferents which terminate in layer IV of prefrontal cortex. However, combined retrograde transport and immunohistochemical techniques failed to reveal the presence of cholecystokinin-positive neurons in the mediodorsal nucleus of the thalamus that project to prefrontal cortex. These findings, and other observations, suggest that the terminal field in layer IV is formed by descending axons that arise from cholecystokinin-containing neurons in layers II and superficial III. This study demonstrates that the cholecystokinin innervation of prefrontal cortex has a laminar specific organization that is preserved across cytoarchitectonic regions. This distribution of immunoreactive structures suggests a distinctive role of cholecystokinin in cortical circuitry that is common to every region of prefrontal cortex.

Immunohistochemical distribution of cholecystokinin, dynorphin A and Met-enkephalin neurons in sheep hypothalamus.

The distribution of cholecystokinin (CCK)-, Met-enkephalin (M-ENK)- and dynorphin (DYN)-like immunoreactive perikarya were examined in the sheep hypothalamus using the peroxidase-anti-peroxidase technique. CCK- and DYN-containing neurons were found primarily in the suprachiasmatic nucleus (SCH) and supraoptic nucleus (SO). No CCK- or DYN-containing neurons were found in the paraventricular nucleus (PVN). M-ENK-containing neurons were found mainly in the PVN of the hypothalamus. In addition, M-ENK neurons were found in the dorsomedial (DMH), lateral (LH), anterior (AH) and periventricular hypothalamic areas. The distribution of these neuropeptides may provide a basis for understanding differences in responsiveness to centrally administered peptides.

Endogenous cholecystokinin drives gallbladder emptying in dogs.

We investigated the effect of fat in the duodenum on the gallbladder emptying in seven dogs prepared with gastric, duodenal, and gallbladder cannulas. Gallbladder volume was measured at 15-min intervals, and venous blood samples were obtained at regular intervals for 2.5 h. Intraduodenal administration of Lipomul (pH 5.0, corn oil) in three different doses (1.1, 2.2, and 4.4 mmol/10 min) resulted in significant increases in gallbladder emptying in a dose-dependent manner (r = 0.8668, P less than 0.001). Likewise, the increase in integrated cholecystokinin (CCK) release in response to Lipomul was also dose dependent (r = 0.7334, P less than 0.001). A statistically significant correlation was found between integrated CCK release and gallbladder emptying in response to Lipomul (P less than 0.001). To determine the role of circulating endogenous CCK on gallbladder emptying effects of intravenous administration of proglumide and a rabbit anti-CCK serum on gallbladder emptying were studied. Gallbladder emptying was virtually abolished by the antiserum. Proglumide not only abolished the emptying but also increased gallbladder volume. Thus we conclude that in dogs the gallbladder emptying in response to fat in the upper small intestine depends on increased circulating endogenous CCK.

Co-existence of cholecystokinin- or gastrin-like peptides with other peptides in the hypophysis and the hypothalamus.

The presence of cholecystokinin and gastrin has been reported in the hypothalamohypophyseal system. These peptides present a peculiar distribution in the hypothalamic nuclei, the median eminence, and the neurohypophysis. CCK and gastrin have close relationships with other peptides like oxytocin, CRF, vasopressin, and the enkephalins; these relationships vary in different projecting areas and in different types of hypothalamic neurons. The functional role of G-CCK in neurosecretion seems to be linked to the role of these closely associated peptides and certainly deserves further investigation.

Iodination with Iodo-gen and radioimmunoassay of cholecystokinin (CCK) in acidified plasma, CCK release, and molecular CCK components in man.

The preparation of a stable fully immunoreactive 125I-labeled CCK39 using a modified Iodo-gen method with high specific radioactivity; the production of an avid and specific cholecystokinin (CCK) antiserum, and a sensitive, precise and specific radioimmunoassay method allowing measurements of fasting plasma CCK in the low picomole per liter range together with the significant rises in plasma CCK following a test meal and duodenal infusion of fat are described. Apparent immunoreactive fasting plasma CCK was eluted from a Sephadex G-50 Fine column in one peak probably representing plasma CCK bound to plasma proteins and nonspecific plasma effects. Apparent immunoreactive postprandial plasma CCK was eluted from a Sephadex G-50 Fine column in four peaks. The first peak probably represents plasma CCK bound to plasma proteins and nonspecific plasma effects; the second peak probably represents component I with a molecular weight between some 5,000 and 30,000; the third peak probably represents component II or CCK33, and the fourth peak probably represents component IV or CCK8.

Extraction and immunochemical characterization of cholecystokinin-like peptides from pig and rat brain.

Two major classes of immunoreactive cholecystokinin peptides (iCCK) have been identified in rat and pig brains: (i) large basic peptides (big iCCK) resembling the 33-amino acid porcine cholecystokinin (pCCK33) in size and charge; (ii) small acidic peptides (small iCCK) resembling the COOH-terminal fragments of CCK. Boiling 0.1 M HCl maximally extracts big iCCK; boiling 0.1 M NaOH maximally extracts small iCCK. The differences in hormonal forms removed by these extractants are not likely to be due to enzymatic conversion during the extraction procedures. Fractionation on Sephadex G-50 and starch gel electrophoresis combined with radioimmunoassay using three antisera of different specificities--(i) directed towards the NH2 terminus of pCCK33, (ii) produced by immunization with COOH-terminal fragment CCK8, (iii) produced by immunization with COOH-terminal fragment CCK4--are consistent with the hypothesis that a major fraction of big iCCK may represent intact cholecystokinin with a COOH-terminal extension, as has recently been suggested for gastrin, a molecule having a COOH-terminal pentapeptide identical with that of cholecystokinin.

Effect of cholecystokinin antiserum on the brain monoamine content in rats.

The effects of intracerebroventricular administration of cholecystokinin (CCK) antiserum )specific for COOH-terminal four amino acids) of CCK were tested in three dilutions on the dopamine (DA), norepinephrine (NE) and serotonin (5-HT) contents of the hypothalamus, amygdala, septum, striatum and cerebral cortex in rats 24 h following application. CCK antiserum decreased the DA and NE contents in the hypothalamus, mesencephalon, amygdala and septum, while it increased the DA content and decreased the NE content of the striatum. It had a slight effect on the 5-HT contents of the amygdala, septum and striatum.