Inescapable shock reduces [3H]Ro 5-4864 binding to "peripheral-type" benzodiazepine receptors in the rat.
[3H]Ro 5-4864 binding to "peripheral-type" benzodiazepine receptors was examined in brain and peripheral tissues of rats subjected to inescapable tailshocks. Two hours after a session of 80 (five-second) inescapable tailshocks, a significant reduction in [3H]Ro 5-4864 (10 mM) binding was observed in membranes from kidney (31%), cerebral cortex (29%), heart (19%) and pituitary (17%) compared to tissues from naive animals. In contrast, inescapable shock did not effect [3H]Ro 5-4864 binding to hippocampal, lung, or adrenal membranes. Scatchard analyses of [3H]Ro 5-4864 binding to renal membranes demonstrated that this session of tailshock reduced the density (Bmax) of "peripheral-type" benzodiazepine receptors without effecting the apparent affinity (Kd) of the radioligand for these sites. The effects of graded stress on [3H]Ro 5-4864 binding to cerebral cortex and kidney were investigated using 5, 20, or 80 (five-second) inescapable shocks. In cerebral cortical membranes, sessions of either 5 or 20 shocks did not affect, while 80 shocks reduced (29%) [3H]Ro 5-4864 (10 mM) binding. In renal membranes, 5 shocks significantly increased (35%), 80 shocks significantly decreased [3H]Ro 5-4864 (10mM) binding (31%). These findings demonstrate that the density of "peripheral-type" benzodiazepine receptors in both peripheral tissues and the central nervous system can be rapidly modulated by stress.
D000704:Analysis of Variance; D000818:Animals; D001570:Benzodiazepinones / Q000378:metabolism*; D004597:Electroshock; D066298:In Vitro Techniques; D007668:Kidney / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000032:analysis / Q000378:metabolism*; D013312:Stress, Physiological / Q000378:metabolism*; D014316:Tritium
D001570:Benzodiazepinones; D011963:Receptors, GABA-A; D014316:Tritium; C028513:4'-chlorodiazepam