INCREASED EXPRESSION OF THE PERIPHERAL-TYPE BENZODIAZEPINE RECEPTOR ISOQUINOLINE CARBOXAMIDE BINDING-PROTEIN MESSENGER-RNA IN BRAIN FOLLOWING PORTACAVAL ANASTOMOSIS

Using RT-PCR, gene expression of the peripheral-type benzodiazepine re ceptor isoquinoline carboxamide-binding protein (PTBR-IBP) was studied in the frontal cortex of rats four weeks following end-to-side portac aval anastomosis, an experimental animal model of hepatic encephalopat hy, or sham operation. Portacaval anastomosis resulted in increased ex pression of PTBR-IBP in frontal cortex and in a concomitant increase i n densities (B-max) of binding sites for the PTBR ligand [H-3]PK11195. In view of the findings that the PTBR modulates the synthesis of neur osteroids with high affinity for excitatory and inhibitory neurotransm itter systems in brain, increased expression of these receptors could be implicated in the pathogenesis of hepatic encephalopathy.