Effects of psychotropic drugs on canine cerebral metabolism and circulation related to EEG--diazepam, clomipramine, and chlorpromazine.

The effects of diazepam, clomipramine, and chlorpromazine upon cerebral metabolism and blood flow were examined separately in 18 dogs. After the administration of diazepam or clomipramine, cerebral cortical oxygen consumption (CMRO2) decreased significantly by a maximum of 17% and 13% of control within 10 minutes and 15 minutes, and returned to control at 120 minutes and 90 minutes, respectively. Chlorpromazine, however, decreased by a maximum of 10% of control, a level which continued throughout the period of observation. It was observed that reduction in CMRglucose was followed by the reduction in CMRO2 at an interval during the early stages of CMRO2 depression. Diazepam produced a significant decrease in CBF accompanied by reduction in CMRO2, but neither clomipramine nor chlorpromazine had any effect on CBF in spite of reduction in CMRO2. Reduction in CMRO2 both with diazepam and clomipramine was accompanied by slow wave activities of EEG, but with chlorpromazine reduction in CMRO2 was accompanied with less pronounced slow wave activities. It was concluded that the three drugs examined were cerebral metabolic depressants.