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Title: Histamine H3 receptors regulate acetylcholine release from the guinea pig ileum myenteric plexus

The effect of selective histamine H3-receptor agonists and antagonists on the acetylcholine release from peripheral nerves was evaluated in the guinea pig longitudinal muscle-myenteric plexus preparations, preloaded with ({sup 3}H)choline. In the presence of H1 and H2 blockade, histamine and (R)-{alpha}-methylhistamine inhibited the electrically-evoked acetylcholine release, being (R)-{alpha}-methylhistamine more active than histamine, but behaving as a partial agonist. The effect of histamine was completely reversed by selective H3-blocking drugs, thioperamide and impromidine, while only submaximal doses of (R)-{alpha}-methylhistamine were antagonized. Furthermore, thioperamide and impromidine enhanced the electrically-evoked acetylcholine release. On the contrary, the new H3-blocker, HST-7, was found substantially ineffective, both as histamine antagonist and as acetylcholine overflow enhancer. These data suggest that histamine exerts an inhibitory control on the acetylcholine release from intestinal cholinergic nerves through the activation of H3 receptors.
Authors:
; ;  [1]
  1. (Univ. of Parma (Italy))
Publication Date:
OSTI Identifier:
5924673
Resource Type:
Journal Article
Resource Relation:
Journal Name: Life Sciences; (USA); Journal Volume: 48:13
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; ACETYLCHOLINE; SECRETION; HISTAMINE; RECEPTORS; BIOCHEMICAL REACTION KINETICS; ANTIHISTAMINICS; GUINEA PIGS; INHIBITION; MUSCLES; NERVES; TRACER TECHNIQUES; TRITIUM COMPOUNDS; AMINES; AMMONIUM COMPOUNDS; ANIMALS; AUTONOMIC NERVOUS SYSTEM AGENTS; AZOLES; DRUGS; ESTERS; HETEROCYCLIC COMPOUNDS; HYDROGEN COMPOUNDS; IMIDAZOLES; ISOTOPE APPLICATIONS; KINETICS; MAMMALS; MEMBRANE PROTEINS; NERVOUS SYSTEM; NEUROREGULATORS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PARASYMPATHOMIMETICS; PROTEINS; QUATERNARY COMPOUNDS; REACTION KINETICS; RODENTS; VERTEBRATES 550201* -- Biochemistry-- Tracer Techniques