SPINAL CORD SITE OF ACTION OF RESORCINOL ISOMERS THAT PRODUCE SYMPATHETIC CIRCULATORY STIMULATION

¹ Department of Pharmacology and Therapeutics, Medical College of South Carolina, Charleston, South Carolina

In rabbit preparations with the basilar artery ligated, injections of resorcinol and its isomers produced marked increments in arterial pressure when injected into the vertebral artery but produced relatively little effect when injected into the common carotid artery.

In dogs with uninterrupted circulatory systems, injections of small doses of resorcinol isomers into the vertebral artery produced prompt increments in ventricular contractile force and arterial pressure. Injections of the same or larger doses into the common carotid artery and the aorta usually were followed by more slowly developing responses of lesser magnitude.

Transection of the cord at C-1 or C-5 levels did not significantly affect responses to vertebral artery, aortic or intravenous injections of resorcinol. Transection at T-1 level moderately reduced these responses.

These experiments are considered to demonstrate that resorcinol and its isomers can act in the spinal cord to produce marked sympathetic circulatory effects.