Experimental local thalamic application of xylocaine through silicone rubber chemode.

Abstract

✓ Utilizing the unique nature of silicone rubber, the authors introduced minute quantities of xylocaine into the centromedian thalamic nucleus of squirrel monkeys via a chronically implanted brain cannula capped with its membrane (Silastic chemode) and tested the monkeys with a conditioned pain response. Intrathalamic xylocaine began to raise the pain threshold at 40 min postinjection, reached maximum effectiveness at 70 min, and maintained this threshold for more than 2 hours.