PATTERNS OF GLUCOSE USE AFTER BICUCULLINE-INDUCED CONVULSIONS IN RELATIONSHIP TO GAMMA-AMINOBUTYRIC-ACID AND MU-OPIOID RECEPTORS IN THE VENTRAL PALLIDUM - FUNCTIONAL MARKERS FOR THE VENTRAL PALLIDUM

Bicuculline-induced convulsions increased glucose use throughout the brain and sharply demarcated the ventral pallidum and globus pallidus. Glucose use in the nucleus accumbens also increased after bicuculline-induced convulsions, except for a circumscribed region in the dorsomedial shell. Since the projection from the nucleus accumbens to the ventral pallidum contains gamma-aminobutyric acid (GABA) and the opioid peptide, enkephalin, the pattern of increased glucose use in the ventral pallidum and nucleus accumbens after bicuculline-induced convulsions was compared to the topography of GABA(A) and mu-opioid receptors. The pattern of glucose use in the nucleus accumbens and ventral pallidum resembled the topography of GABA(A), but differed from that of mu-opioid receptors. Bicuculline may disinhibit GABAergic efferents to the ventral pallidum resulting in a dramatic increase in glucose use within striatopallidal synaptic terminals as well as in local terminals of the pallidal projection neurons.