[Effect of propranolol and pindolol on carotid reflexes induced by lobeline]

1. On the carotid reflexogenic zone, pindolol provokes a proper action which consists in a respiratory excitation and a diminution of cardiac rate accompanied by decrease of blood pressure. 2. The infiltration of the tissues of the carotid bifurcation with a solution of propranolol annuls temporarily the carotid lobeline reflexes probably by the propranolol local anaesthetic action. 3. The beta blockers propranolol and pindolol, when injected in the vessels of the carotid zone, inhibits temporarily the carotid reflexes of lobeline by a local action on the carotid body. These results suggest that in the excitation of the receptor system of the carotid body by lobeline interferes an adrenergic mechanism.