Cerebral ventricular transport and uptake: importance for CCK-mediated satiety

Effects of peptides on animal and human behavior: a review of studies published in the first twenty years of the journal Peptides

This review catalogs effects of peptides on various aspects of animal and human behavior as published in the journal Peptides in its first twenty years. Topics covered include: activity levels, addiction behavior, ingestive behaviors, learning and memory-based behaviors, nociceptive behaviors, social and sexual behavior, and stereotyped and other behaviors. There are separate tables for these behaviors and a short introduction for each section.

Immunolocalization of tripeptidyl peptidase II, a cholecystokinin-inactivating enzyme, in rat brain

Tripeptidyl peptidase II (EC 3.4.14.10) is a serine peptidase apparently involved in the inactivation of cholecystokinin octapeptide [Rose C. et al. (1996) Nature 380, 403-409]. We have compared its distribution with that of cholecystokinin in rat brain, using a polyclonal antibody raised against a highly purified preparation for immunohistochemistry at the photon and electron microscope levels. Tripeptidyl peptidase II-like immunoreactivity was mostly detected in neurons, and also in ependymal cells and choroid plexuses, localizations consistent with a possible participation of the peptidase in the inactivation of cholecystokinin circulating in the cerebrospinal fluid. Immunoreactivity was mostly detected in cell bodies, large processes and, to a lesser extent, axons of various neuronal populations. Their localization, relative to that of cholecystokinin terminals, appears to define three distinct situations. The first corresponds to neurons with high immunoreactivity in areas containing cholecystokinin terminals, as in the cerebral cortex or hippocampal formation, where pyramidal cell bodies and processes surrounded by cholecystokinin axons were immunoreactive. A similar situation was encountered in many other areas, namely along the pathways through which cholecystokinin controls satiety, i.e. in sensory vagal neurons, the nucleus tractus solitarius and hypothalamic nuclei. The second situation corresponds to cholecystokinin neuronal populations containing tripeptidyl peptidase II-like immunoreactivity, as in neurons of the supraoptic or paraventricular nuclei, axons in the median eminence or nigral neurons. In both situations, localization of tripeptidyl peptidase II-like immunoreactivity is consistent with a role in cholecystokinin inactivation. The third situation corresponds to areas with mismatches, such as the cerebellum, a region devoid of cholecystokinin, but in which Purkinje cells displayed high tripeptidyl peptidase II-like immunoreactivity, possibly related to a role in the inactivation of neuropeptides other than cholecystokinin. Also, some areas with cholecystokinin terminals, e.g., the molecular layer of the cerebral cortex, were devoid of tripeptidyl peptidase II-like immunoreactivity, suggesting that processes other than cleavage by tripeptidyl peptidase II may be involved in cholecystokinin inactivation. Tripeptidyl peptidase II-like immunoreactivity was also detected at the ultrastructural level in the cerebral cortex and hypothalamus using either immunoperoxidase or silver-enhanced immunogold detection. It was mainly associated with the cytoplasm of neuronal somata and dendrites, often in the vicinity of reticulum cisternae, Golgi apparatus or vesicles, and with the inner side of the dendritic plasma membrane. Hence, whereas a fraction of tripeptidyl peptidase II-like immunoreactivity localization at the cellular level is consistent with its alleged function in cholecystokinin octapeptide inactivation, its association with the outside plasma membrane of neurons remains to be confirmed.

Production of antisera to acidic fibroblast growth factor and their application to immunohistochemical study in rat brain

Antisera against acidic fibroblast growth factor purified from bovine brain were produced in rabbits and used for immunohistochemical study of the rat brain. When examined in an immunospot assay using a nitrocellulose membrane, the best antibody was capable of detecting 80 fmol of acidic fibroblast growth factor but failed to react even with up to 5 pmol of basic fibroblast growth factor. Using this antiserum, the immunohistochemical distribution of acidic fibroblast growth factor was examined in rat brain. Acidic fibroblast growth factor-like immunoreactivity was localized mainly in a subpopulation of ependymal cells and tanycytes, as well as in some glial cells. Positive ependymal cells were observed throughout the walls of ventricles, including the third ventricle and cerebral aqueduct. Immunoreactive processes of tanycytes were found extending from the ventral wall of the third ventricle to the brain parenchyma and surface. The most intense immunostaining was observed in circumventricular organs such as the organum vasculosum laminalis terminalis and the subfornical organ. Particularly in the latter organ, there was an extremely dense plexus of immunoreactive fibers and processes around the wall of capillaries. The present results suggest that the effects of acidic fibroblast growth factor on brain functions may be exerted through the circumventricular organs and/or ependymal cells.

Effect of chronic intracerebroventricular infusion of cholecystokinin on respiration and sleep

We investigated the effect of chronic intracerebroventricular infusion of the sulfated cholecystokinin octapeptide (CCK-8S) on sleep pattern and respiratory rate. The results indicate a depression of respiratory rate during Non-REM and REM sleep as well as an increase in the number of REM periods occurring per hour of Non-REM sleep. It is suggested that central release of CCK-8S is capable of modulating the automatic regulation of respiration during sleep and altering the normal sleep-waking pattern.

Central nervous system effects of peptides, 1980-1985: a cross-listing of peptides and their central actions from the first six years of the journal Peptides

A tabular synopsis is presented for articles concerned with the effects of peptides on the central nervous system that appeared in the journal Peptides from 1980-1985. A table arranged alphabetically by peptide and one arranged by effects, both listing routes of injection, species, direction of change, and qualifying notes, provides easy cross-referencing of peptides and their effects. Over 80 peptides and over 135 effects are listed. The list of peptides includes, but is not limited to: ACTH, angiotensin, bombesin, bradykinin, calcitonin, casomorphin, CCK, ceruletide, CGRP, CRF, dermorphin, DSIP, dynorphin, endorphins, enkephalins, GRF, gastrin, LHRH, litorin, metkephamid, MIF-l, motilin, MSH, NPY, NT, oxytocin, ranatensin, sauvagine, substances P and K, somatostatin, TRH, VIP, vasopressin, and vasotocin. The list of effects includes, but is not limited to: aggression, alcohol, analgesia, attention, avoidance, behavior, cardiovascular regulation, catalepsy, conditioned behavior, convulsions, dopamine binding and metabolism, discrimination, drinking, EEG, exploration, feeding, fever, gastric secretion, GI motility, grooming, learning, locomotor behavior, mating, memory, neuronal activity, open field, operant behavior, rearing, respiration, satiety, scratching, seizure, sleep, stereotypy, temperature, thermoregulation and tolerance.

Central nervous system cholecystokinin and the control of feeding

There is still much to learn of the sites and mechanisms of action of brain CCK peptides and their interaction with other brain peptides and neurotransmitters. The findings obtained from studies in sheep and other species provide evidence for brain CCK peptides functioning as important transmitters of hunger and satiety signals. We have hypothesized that signals, either neural or humoral, peripherally generated as a result of feeding induce secretion of CCK from specific (paraventricular) brain sites into the CSF (FIG. 1). Specialized ependymal cells, such as tanycytes, may take up CCK from the CSF for transport to receptor sites which mediate CCK's specific functions (such as changes in rumen motility, suppression of insulin secretion, and behavioral satiety). Evidence also exists to indicate the involvement of specific hypothalamic sites in either the release or the action of CCK.