Journal of Neuroscience, Vol 2, 853-860, Copyright © 1982 by Society for Neuroscience
Effects of gamma-aminobutyric acid agonist and antagonist drugs on local cerebral glucose utilization
JM Palacios, MJ Kuhar, SI Rapoport and ED London
The [14C]2-deoxy-D-glucose method of Sokoloff et al. (Sokoloff, L., M.
Reivich, C. Kennedy, M.H. Des Rosiers, C. S. Patlak, K. D. Pettigrew, O.
Sakurada, and M. Shinohara (1977) J. Neurochem. 28:897-916) weas used to
study local cerebral glucose utilization (LCGU) in rats treated with
gamma-aminobutyric acid (GABA) agonist (muscimol and 4,5,6,7-
tetrahydroisoxazolo[5,4-C]pyridin-3-ol, THIP) and antagonist (bicuculline)
drugs. It was of interest to determine if the pattern of LCGU responses to
GABA agonists and antagonists administered systemically in vivo would
reflect the known distributions of markers for central GABAergic synapses.
The patterns of LCGU responses to muscimol and THIP generally were similar.
Most brain regions showed dose-dependent decreases in LCGU; others showed
no effects; but the red nucleus showed an increase. The GABA antagonist
bicuculline produced convulsions and variable LCGU responses, depending on
the time of administration. Bicuculline also partially antagonized the
depressant effects of muscimol of LCGU. The magnitudes and distribution of
in vivo cerebral metabolic responses to specific GABA agonists were not
correlated simply with markers for GABAergic synapses. This lack of
correlation indicates that additional factors, such as neural circuitry,
regulate the LCGU responses to GABAergic drugs.