Pharmacology of bovine pulmonary vein anaphylaxis in vitro

1. The bovine pulmonary vein contracts in response to acetylcholine, histamine, 5-hydroxytryptamine and bradykinin. The tissue is particularly sensitive to 5-hydroxytryptamine (>0.1 ng/ml). Specific Schultz-Dale reactions were elicited in the pulmonary vein in response to horse plasma.2. The Schultz-Dale reaction is inhibited both by antihistaminics and by the anti-5-hydroxytryptamine agent methysergide, but not by atropine.3. Sodium meclofenamate inhibited anaphylactic contraction but showed a strong tendency to antagonize many agonists indiscriminately.4. Disodium cromoglycate (DSCG: 100 mug/ml) which inhibits some immunological reactions of mast cells, and diethylcarbamazine citrate (DECC: 50 mug/ml) which inhibits slow-reacting substance of anaphylaxis (SRS-A) elaboration, each inhibited anaphylaxis incompletely (50% or less). However, a combination of DSCG and DECC virtually abolished the Schultz-Dale reaction in this preparation. It is tentatively suggested that the component of the anaphylactic contraction which is resistant to cromoglycate but sensitive to diethylcarbamazine could be due to SRS-A.5. The bovine pulmonary Schultz-Dale reaction appears to be a complex interaction of histamine, 5-hydroxytryptamine, SRS-A and possible other agents including kinins.