Experimental studies on central benzodiazepine receptors in the brains of hepatic encephalopathy rats.

With radioligand binding assay, we studied the central benzodiazepine receptors (CBR) in the different regions of brain including the telencephalon, diencephalon, brain stem and cerebellum in a rat model of hepatic encephalopathy (HE) induced by partial hepatectomy following carbon tetrachloride (CC1(4)) intoxication and in the controls. Affinities (Kd) and densities (Bmax) of [3H]-flunitrazepine binding to crude synaptic membranes in the telencephalon of HE rats were obviously increased as compared with those of the controls. It was only in the diencephalon, the brain stem and the cerebellum of HE rats that increased Bmax values were observed, while the Kd values remained unchanged. The results support the recent suggestion that the alterations of CBR play a significant role in the pathogenesis of HE. Among the ranges of the alterations of CBR in the HE rats, the telencephalon ranked first, the brain stem second, the cerebellum third, and the diencephalon last.