Inhibitory action of antimycin A on histamine release from isolated rat mast cells.

Abstract

Abstract: Pretreatment of isolated rat mast cells with antimycin A (0.03 μM or more) inhibited histamine release induced by subsequent exposure to compound 48/80 or exogenous ATP. When the mast cells were simultaneously exposed to antimycin A (0.1 μM) and the releasing agents, compound 48/80, but not ATP, released histamine. In contrast, exogenous ATP, but not compound 48/80, induced histamine release from cells which after pretreatment with antimycin A were diluted to an ineffective concentration of the inhibitor with a solution containing the releasing agent. The different effects of antimycin A on histamine release induced by compound 48/80 and exogenous ATP can be explained by the difference in the time courses between the release reactions. The ATP content in mast cells was gradually reduced during treatment with antimycin A (0.2 μM) so that after 3 min. only about 30 % of the original content remained. Concomitantly, the ability of the cells to release histamine when exposed to compound 48/80 decreased. This suggests that histamine release induced by compound 48/80 is dependent on the ATP content in the cells at the time of exposure to the releasing agent.