Pentobarbital sleeping time and waking blood levels in spontaneously hypertensive rats.

Pentobarbital sleeping times and blood levels on arousal were determined in spontaneously hypertensive rats (SHR) and normotensive controls (WKR). Sleeping time for SHR was significantly less than for WKR, but blood levels of [14C]pentobarbital at awakening were not significantly different. The shorter sleeping time in SHR appears not to result from decreased brain sensitivity to pentobarbital. Instead, SHR appear to differ from WKR in the rate of metabolic clearance of the drug or in the distribution of the drug between blood and brain.