ELECTROPHYSIOLOGIC ANALYSIS OF THE SITE OF ACTION OF DOXAPRAM HYDROCHLORIDE

¹ A. H. Robins Research Laboratories, Richmond, Virginia

Intravenously administered doxapram HCl in doses of 0.2 to 1.0 mg/kg selectively stimulated respiratory centers in the medulla. Higher doses of the drug (3 mg/kg) stimulated the spinal cord, apparently by direct action; after substantially larger doses, higher centers in the brain were stimulated. No direct evidence of action of the drug on the reticular activating system could be shown; however, thalamic recruitment and cortical after-discharge were reduced, and electroencephalogram (EEG) desynchronization was produced in intact, unanesthetized, paralyzed animals and in cerveau isolé preparations. These effects could have resulted from mild stimulatory action on the anterior part of the reticular formation.