Sex differences in GABA/benzodiazepine receptor changes and corticosterone release after acute stress in rats
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Since many hormonal indices of stress responsiveness are sexually dimorphic in rats, we examined sex differences and the effects of gonadectomy on the stress-related changes in GABAA/benzodiazepine receptors in rats. Intact or ovariectomized female rats displayed a markedly greater corticosterone response and a more pronounced increase in benzodiazepine receptors than males (intact or orchidectomized) after acute handling or swim stress. Swim stress increased benzodiazepine receptor density without modifying affinity in cortex, hippocampus, and hypothalamus. Corticosterone treatment induced benzodiazepine receptor levels comparable to those seen after swim stress in all hormone groups. Handling stress also enhanced cortical low-affinity GABAA receptor levels in males and ovariectomized females. Both GABA and benzodiazepine receptor levels were positively correlated with circulating corticosterone levels in female, but not male, groups. GABA/benzodiazepine coupling was unaffected by stress or hormonal status. These sexual dimorphisms in hormonal responses to stress may help elucidate the causes and consequences of stress-induced changes in the GABAA/benzodiazepine receptor complex.
Key wordsGABA receptors Benzodiazepine receptors Stress Corticosterone Sex differences Rat
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- Barbaccia ML, Guarneri P, Berkovich A, Wambebe C, Guidotti A, Costa E (1989) Studies on the endogenous modulator of GABAA receptors in human brain and CSF, In: Barnard A, Costa E (eds) Allosteric modulation of amino acid receptors: therapeutic implications. Raven Press, New York, pp 125–138Google Scholar
- Biggio G (1983) The action of stress, β-carbolines, diazepam, and Ro 15–1788 on GABA receptors in the rat brain. In: Biggio G, Costa E (eds) Benzodiazepine recognition site ligands: biochemistry and pharmacology. Raven Press, New York, pp 105–119Google Scholar
- Gallucci WT, Schneiderman L, Smith MA, Whitfield HJ, Gold PW (1991) Male and female differences in response to restraint stress in rats. Soc Neurosci Abstr 17:1557Google Scholar
- Granberry AA, Bunnell BN, Mougey EH, Meyerhoff JL (1989) Estrogen mediates sex differences in adrenal cortical responses to stress. Soc Neurosci Abstr 15:716Google Scholar
- Handa RJ, Lorens SA, Nunley KR, George M, Hejna G (1991) Androgen inhibits the neuroendocrine and neurochemical response to novelty stress. Soc Neurosci Abstr 17:1556Google Scholar
- Lowry OH, Rosebrough HJ, Farr AL, Randall RJ (1951) Protein measurement with the Folin phenol reagent. J Biol Chem 193:265–275Google Scholar
- Lundeen JE, Gordon JH (1986) Computer analysis of binding data. In: Receptor binding in drug research. Dekker, New York, pp 31–49Google Scholar