The effect of a selective 5‐HT2 antagonist, ketanserin, on the pulmonary responses to Escherichia coli endotoxin

5-Hydroxytryptamine (5-HT, 5-160 microgram kg-1) injected intravenously in pentobarbitone-anaesthetized, open-chest cats caused dose-dependent increases in pulmonary arterial and intratracheal pressures. There was also a marked systemic hypotension and bradycardia. The pulmonary effects were completely prevented by ketanserin (0.2 mg kg-1), a selective 5-HT2 blocking drug. Ketanserin (0.2 mg kg-1) itself lowered arterial pressure (by 30-40 …