[Anti-anaphylactic properties of verapamil. First experimental assessment]

1. In order to confirm the potential anti-anaphylactic properties of verapamil, the effects of this calcium antagonist were assessed on several experimental models: anaphylactic shock in mice, passive cutaneous anaphylaxis in Rats, and degranulation of Rat peritoneal mast cells. 2. At a dose of 5 mg/kg IP, half-an-hour before challenge, verapamil decreased systemic anaphylaxis-induced lethality significantly. On the reverse, in the same conditions, it was unable to inhibit passive cutaneous anaphylaxis at 0.1-0.5-1 or 10 mg/kg; it did even increase it at a dose of 5 mg/kg IP over the last 3 days. However, specific degranulation of rat peritoneal mast cells was significantly decreased after in vitro incubation with verapamil (0.25 and 1.25 micrograms/ml or after pretreatment with 5 mg/kg/day over 3 days). 3. These early results confirm the hypothesis of verapamil anti-anaphylactic properties whose consequences warrant further investigation.