Inferior cardiac nerve activity in the cat during superfusion of the vascularly isolated carotid sinus with propranolol.

1 Inferior cardiac nerve activity in 9 cats was in inverse relationship to the pressure maintained in the systemically isolated and perfused carotid sinus. 2 Perfusion with propranolol produced no change in this relationship at a concentration of 5.0 microgram/ml, but abolished it at 50.0 microgram/ml. 3 The results suggest that concentrations of propranolol which have been reported to enhance the sensitivity of the carotid sinus to pressure do not enhance one neurophysiological component of the reflex depressor response.