STUDIES ON THE TRANSPORT OF MORPHINE OUT OF THE PERFUSED CEREBRAL VENTRICLES OF RABBITS

¹ Department of Pharmacology, Health Sciences Center, University of Minnesota Medical School, Minneapolis, Minnesota

Artificial cerebrospinal fluid was perfused between the lateral ventricle and the cisterna magna of anesthetized rabbits. This perfusion system was used to study the transport of morphine out of the ventricles. The passage of morphine from the perfused ventricles to the blood appeared to be a simple diffusion process since the percentage of morphine removed from the perfusion fluid remained constant over a wide range of inflow concentrations in the ventriculocisternal perfusion system. This transport was not inhibited by time concurrent perfusion with structurally related compounds such as codeine, ethylmorphine and naloxone, with organic basic compounds such as cocaine, N-methylnicotinamide and quinine, with an organic acidic compound, p-aminohippurate or with inhibitors such as dinitrophenol and ouabain.