The involvement of nitric oxide (NO) in the CGRP-induced behavior of rats

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.

The action of pituitary adenylate cyclase activating polypeptide (PACAP) on passive avoidance learning. The role of transmitters

In the present study, the action of PACAP 38 on one-way passive avoidance learning was investigated. PACAP-38 was administered into the lateral brain ventricle and the latency of the passive avoidance response was measured 24 h later. In order to study the possible roles of various neurotransmitters in mediating the action of PACAP on the consolidation of passive avoidance learning, the animals were pre-treated with receptor blockers in doses that per se proved to be ineffective. PACAP facilitated the learning, the consolidation of learning and the retrieval of the passive avoidance response. The following receptor blockers attenuated the action of PACAP on this consolidation: haloperidol, phenoxybenzamine, propranolol and methysergide. An antagonist of PACAP 38, PACAP 6-38, and also nitro-L-arginine (the latter blocks the enzyme nitric oxide synthase) thereby inhibiting the formation of NO from L-arginine, completely blocked the action of PACAP 38 on consolidation. The following receptor blockers were ineffective: naloxone, bicuculline and atropine. The presented data suggest that PACAP 38 is able to improve the learning and memory processes in a passive avoidance paradigm. In this action, the PACAP 38 receptor and NO are important mediators. Dopaminergic, alpha- and beta-adrenergic mediation and serotonin receptors modified the action of PACAP 38, but they are probably not of great importance.

Neurotransmitter-mediated open-field behavioral action of CGRP

The effects of central administration of calcitonin gene-related peptide (CGRP) on open-field activity were examined in male rats. Three doses (250 ng, 500 ng and 1 microg) of CGRP given intracerebroventricularly (i.c.v.) were tested on the ambulatory, rearing and grooming activities of the animals. One microg of peptide significantly decreased the ambulatory activity and increased the rearing and grooming activities 30 min after the treatment. The animals were pretreated with different receptor antagonists in doses which by itself did not affect the behavioural paradigm. The decrease in ambulation induced by CGRP was antagonized by acetylcholine-, opioid-, 5HT-receptor and beta-adrenoceptor antagonists. CGRP induced increase in rearing activity was blocked by naloxone, phenoxybenzamine and propranolol. The CGRP-induced increase in grooming behavior was prevented by atropine, haloperidol, naloxone, methysergide and propranolol. The results suggest that different neurotransmitter systems are involved in the action of CGRP on open-field behavior in rats.

Effects of peptides: a cross-listing of peptides and their central actions published in the journal Peptides from 1994 through 1998

Effects of peptides on the central nervous system are presented in two ways so as to provide a cross-listing. In the first table, the peptides are listed alphabetically. In the second table, the central nervous system effects are arranged alphabetically. No longer can there be any doubt that peptides affect the central nervous system, sometimes in several ways.