Effects of pentobarbital on cerebral monoamine turnover in rats

Cerebral monoamine turnover in the 5 to 7 different regions of the brain was evaluated in rats. Monoamine turnover in pentobarbital (PB) anesthetized rats was compared to those in awake rats. In the noradrenergic system, noradrenaline levels after pargyrine treatment in PB rats did not differ from those in awake rats in 7 regions examined, while 3-methoxy 4-hydroxyphenylglycol levels after probenecid was higher in PB rats in5 regions. In the dopaminergic system, L-Dopa levels after NSD 1015 and dopamine (DA) levels after pargyrine in the striatum in PB rats were lower. Higher DA levels after pargyrine in the midbrain and cerebral cortex were accompanied by lower levels of homovanilic acid (HVA) after probenecid, 3,4-dihydroxyphenylacetic acid/DA and HVA/DA. In the serotonergic system, lower 5-hydroxytryptophan levels after NSD 1015 were observed while higher serotonin levels after pargyrine were found in the hypothalamus, hippocamous and cerebral cortex. From these results, it appears that PB anesthesia has differential effects on monoamine turnover depending on the specific regions.