Effect of changes in [Ca++] on relaxation of the isolated rat stomach in response to vagal stimulation
Bettini, V.; Cessi, C.; Legrenzi, E.; Sandini, C.
Bollettino della Societa Italiana di Biologia Sperimentale 53(10): 845-849
1977
ISSN/ISBN: 0037-8771 PMID: 588357 Document Number: 124067
When a vagally intact, isolated stomach preparation from an albino rat, suspended in Krebs solution, undergoes vagal stimulation, either contraction or relaxation may result, depending on the parameters of stimulation. When the Ca2+ concentration is increased substantially from a standard reference level of 2.54 mM, the relaxation that can be obtained by appropriate vagal stimulation is abolished or reversed to contractions. This reduction of relaxation can be explained by assuming that Ca2+ antagonizes the release of the relaxing vagal mediator or inhibits its liberation. This cannot explain the abolition of relaxation by vagal stimulation. The explanation may be that Ca2+ facilitates the liberation of acetylcholine.