[Secretory activity of mast cells in the presence of cholinergic agonists]

Mast cells from rat peritoneal fluid were studied under cholinergic stimulus. The cells were purified by a continuous Ficoll gradient and were challenged with acetylcholine and carbamylcholine. The preparations showed the typical dose-response pattern against compound 48/80 with a dose interval of 0.5-1 microM that clearly increased the secretion. However, the histamine release elicited by increasing concentrations of acetylcholine and carbamylcholine was of little magnitude and similar for all the concentrations; this kind of response has not a dose-response profile and does not appear to be explained by the presence of a cholinergic receptor on the mast cell cellular membranes. The cholinergic agents neither stimulated directly the mast cells nor did they cause any variation in the 48/80 response. The histamine release pattern obtained with these agents cannot support the hypothesis of a primary cholinergic receptor on mast cells. However, if such receptor existed, its action could only be of secondary importance, and in fact such action was not manifested with the compound 48/80.