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γ‐Aminobutyric Acid B Receptor Activation Modifies Agonist Binding to β‐Adrenergic Receptors in Rat Brain Cerebral Cortex
Author(s) -
Scherer Roberta W.,
Ferkany John W.,
Karbon E. William,
Enna S. J.
Publication year - 1989
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1989.tb11806.x
Subject(s) - agonist , gabab receptor , baclofen , receptor , bicuculline , chemistry , aminobutyric acid , cerebral cortex , gaba receptor , binding site , gabaa receptor , medicine , endocrinology , biochemistry , biology
The interaction of isoproterenol with β‐adrenergic receptor (βAR) binding sites was measured in membranes prepared from rat brain cerebral cortical slices previously incubated in the presence or absence of γ‐aminobutyric acid (GABA) receptor agonists. Both GABA and baclofen, but not isoguvacine, altered βAR agonist binding by increasing the affinity of both the low‐ and high‐affinity binding sites and by increasing the proportion of low‐affinity receptors. The response to baclofen was stereoselective, and the effect of GABA was not inhibited by bicuculline. The results suggest that GABA B , but not GABA A , receptor activation modifies the coupling between βAR and stimulatory guanine nucleotide‐binding protein, which may in part explain the ability of baclofen to augment isoproterenol‐stim‐ulated cyclic AMP accumulation in brain slices.