AJP - Gastrointestinal and Liver Physiology, Vol 239, Issue 4 255-G260, Copyright © 1980 by American Physiological Society
Histamine and cAMP as possible mediators of acetylcholine-induced acid secretion
E. B. Ekblad
Data are presented in support of the role of histamine and adenosine
3',5'-cyclic monophosphate (cAMP) as mediators of acetylcholine-induced
acid secretion in frog gastric mucosa. These data also support the notion
that acetylcholine-induced alkaline secretion is mediated by guanosine
3',5'-cyclic monophosphate (cGMP). Tissue cAMP and cGMP and rates of acid
secretion and histamine release were measured in in vitro preparations of
frog gastric mucosa that had been stimulated by acetylcholine. A transient
increase in each variable was observed, the sequence of transient maxima
being histamine release, cGMP, cAMP, and acid secretion. Atropine, an
anticholnergic agent, eliminated all four transient increases, the
variables remaining at resting levels. Metiamide, a H2-antagonist, modified
the changes observed after acetylcholine stimulation. The acid secretion
transience was abolished and the transient increase in tissue cAMP was
greatly diminished, whereas the tissue of cGMP transience and histamine
release transience remained unchanged. A model is proposed in which
acetylcholine initiates two different processes, acid and alkaline
secretions.
