[An experimental study on brain-gut peptide receptors in brains of rats with hepatic encephalopathy]

By means of radioligand binding assay, two brain-gut peptide, somatostatin (SS) and vasoactive intestinal peptide (VIP), receptors in crude synaptosomal membranes of brain were investigated in rats with hepatic encephalopathy (HE) and in controls. In HE rats and in controls, the maximal binding capacity (Bmax) were 238.0 +/- 14.2 and 200.0 +/- 11.3 fmol/mg of protein, the dissociation constant (Kd) was 3.99 +/- 0.22 and 3.89 +/- 0.34 nM respectively for SS receptors. The Bmax values of VIP receptors in HE rats and in controls were 9.56 +/- 0.29 and 10.92 +/- 0.44 fmol/mg of protein, the Kd values were 0.28 +/- 0.01 and 0.29 +/- 0.02 nM, respectively. Increased Bmax values of SS receptors (P < 0.005) and decreased Bmax values of VIP receptors (P < 0.002) were observed in HE rats as compared with those in controls. The results suggest that changes of brain-gut peptide receptors in brains play a significant role in the pathogenesis of HE.