An experimental study on somatostatin receptors in the brains of hepatic encephalopathy rats

The present study was undertaken to evaluate the effect of somatostatin (SS) receptor, a brain-gut peptide receptor which is capable of inhibiting central neurons, on the pathogenesis of hepatic encephalopathy (HE). By means of radioligand binding assay, SS receptors in crude synaptosomal membrane of rat brains were investigated in a rat model of HE induced by partial hepatectomy following carbon tetrachloride intoxication and in controls. Binding to SS receptor was studied using 125 I-SS as radioligand. Scatchard analysis of binding data was linear, yielding a dissociation constant (Kd) of 3.99 +/- 0.22 nmol/L and a maximal binding capacity (Bmax) of 238 +/- 14.2 fmol/mg of protein in HE rats. Only increased Bmax values were observed (P < 0.005), while the Kd values were statistically unchanged (P > 0.50), in HE rats as compared with those in controls. The results suggest that the changes of SS receptors in brains play a significant role in the pathogenesis of HE. The mechanism of HE induced by the alterations of SS receptors in the brains was discussed in this paper.