Autoradiographic localization of the GABAA receptor agonist [3H]-muscimol within rat kidney.

By the use of combined radioreceptor binding and autoradiographic techniques, the pharmacological characteristics of (3H)-muscimol binding and the localization of the label were studied. (3H)-Muscimol was bound by sections of rat kidney in a manner consistent with the existence of specific gamma-aminobutyric acid 'A' (GABAA) receptors with KD and Bmax values of 23.7 nmol/l and 1.15 pmol/mg tissue, respectively. (3H)-Muscimol was bound by convoluted tubules of the renal cortex and by the collecting tubules. Our findings demonstrating the existence of recognition sites for the GABAA receptor agonist muscimol in the kidney suggest that GABA has a role in renal function.