THE VASOCONSTRICTOR AND VASODILATOR EFFECTS OF PROCAINE

Publisher Website
Google Scholar
Abstract
Procaine hydrochloride (15 mg/kg) administered intravenously raises the systemic arterial pressure in spinal cats but lowers it in cats anaesthetized with pentobarbital. The rise in blood pressure is not due to release of adrenaline or noradrenaline since a pressor response to procaine still occurs after phenoxybenzamine. Procaine also increases the blood pressure in pentobarbital-anaesthetized cats after the administration of phenoxybenzamine or reserpine. The perfusion pressure in the isolated hind limb perfused at a constant flow was increased by procaine given intra-arterially in spinal cats. In contrast, procaine lowered the perfusion pressure in the hind limb of pentobarbital-anaesthetized cats. The results are consistent with a direct vasoconstrictor effect of procaine on peripheral vessels which is masked when sympathetic vasomotor tone is high. The fall in blood pressure after procaine in pentobarbital-anaesthetized cats may be due to an effect of the drug on terminal nerve endings.