Mu and kappa(1) opioid-stimulated [S-35]guanylyl-5 '-O-(gamma-thio)-triphosphate binding in cynomolgus monkey brain

Agonist-stimulated [S-35]GTP gamma S binding allows the visualization of re ceptor-activated G-proteins, thus revealing the anatomical localization of functional receptor activity. Ln the present study, agonist-stimulated [S-3 5]GTP gamma S binding was used to demonstrate mu and kappa(1) opioid-stimul ated [S-35]GTP gamma S binding in tissue sections and membranes from cynomo lgus monkey brain using DAMGO and U50,488H, respectively. Concentrations of agonists required to produce maximal stimulation of [S-35]GTP gamma S bind ing were determined in membranes from the frontal poles of the brain. Recep tor specificity was verified in both membranes and sections by inhibiting a gonist-stimulated [S-35]GTP gamma S binding with the appropriate antagonist . Mu opioid-stimulated [S-35]GTP gamma S binding was high in areas includin g the amygdala, ventral striatum, caudate, putamen, medial thalamus and hyp othalamus. Dense mu-stimulated [S-35]GTP gamma S binding was also found in brainstem nuclei including the interpeduncular nucleus, parabrachial nucleu s and nucleus of the solitary tract. Kappa(1) opioid-stimulated [S-35]GTP g amma S binding was high in limbic and association cortex, ventral striatum, caudate, putamen, globus pallidus, claustrum, amygdala, hypothalamus and s ubstantia nigra. These results demonstrate the applicability of [S-35]GTP gamma S autoradiog raphy to examine receptor-activated G-proteins in the primate brain and rev eal functional mu and kappa(1) opioid receptor activity that may contribute to the reported central nervous system effects of opiates. (C) 1999 IBRO. Published by Elsevier Science Ltd.