Studies on the Mechanism of Biogenic Amine Release

摘要

Analysis brazilian rattlesnake venom permitted isolation of histamine releasing factor. Agent active very low concentrations, enzymatic, possibly chymotrypsin-like nature. Action only exerted on metabolically active rat mast cells, can separate from crotactin, neurotoxic component rattlesnake venom, and phospholipase A. In vitro evidence indicates sensitivity mast cells to partial degranulation by catecholamines. Specific inhibitors indicate effect is an action on alpha type receptors. In vivo studies indicate degranulation mesentery mast cells resulting from splanchnic stimulation; i.v. tyramine or adrenaline also selectively inhibited by alpha but not beta sympatholytic drugs. Alkaline pH, iodoacetate, or dinitrophenol in absence of glucose, repress release histamine from isolated rat lung by 20 ug/ml but not that by 1 mg/ml compound 48/80. Suggest 48/80 evokes histamine release rat mast cells two ways: induced by compound at low concentrations, dependent on cell metabolism, similar to release by anaphylactic reaction; higher concentrations of drug, an unspecific effect involves displacement intracellular, bound histamine by excess of basic releaser. (Author)