EFFECT OF PERTUSSIS AND BETA ADRENERGIC-BLOCKING AGENTS ON MAST-CELLS

Pertussis vaccine injected i.p. in doses known to cause hypersensitization resulted in a marked decrease in the number of mast cells recovered from the peritoneal washings of rats and mice. A significant reduction was obtained as early as 1 day after pertussis injection of 109 cells in rats, and was marked after 5 to 7 days. A maximum reduction in the number of mast cells was obtained by a dose of 20 .times. 109 cells. There was no detectable histamine biological activity in the supernatant from peritoneal washings obtained after 10 min, 60 min, and 24 h from control and pertussis-treated rats, indicating that pertussis did not cause degranulation of mast cells in vivo. The histamine content in the precipitated mast cell pellets from control rats was much higher than the corresponding histamine content from pertussis-treated rats. In rats and mice, propranolol and other .beta. adrenergic-blocking agents caused degranulation of mast cells in the peritoneal washings in vitro. Practolol was the least effective .beta. adrenergic-blocking agent in degranulating mast cells. Catecholamines, histamine, 6-hydroxydopamine, methacholine and pertussis failed to cause any degranulation. Isoproterenol protected the mast cell against the degranulation induced by propranolol. Propranolol caused bluing in rat and mouse skin when injected id [intradermally]. Mast cells from control and pertussis-injected rats were equally sensitive to propranolol in vitro. The low recovery of mast cells from the peritoneal washings of rats and mice is probably due to mobilization of mast cells away from the peritoneum.