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标题：Potentiated Modulation of Pregnolone on GABAA Receptors in Behaviorally Stressed Borderline-Hypertensive Rats
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作者：Hyoung Chul Choi ; Jong-Yeon Kim ; Jong-Bum Lee 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：2004
卷号：27
期号：1
页码：122-124
DOI：10.1248/bpb.27.122
出版社：The Pharmaceutical Society of Japan
摘要：The modulatory effects of behavioral stress on [³H]flunitrazepam, an agonist for the central-type benzodiazepine receptor binding to the GABA_A-benzodiazepine receptor complex, in borderline hypertensive rats (BHR) were examined. In repeatedly immobilized (for 2 weeks, for 2 h/d) BHR, enhancement of [³H]flunitrazepam binding to the receptor was observed to be potentiated. The percent enhancement of [³H]flunitrazepam binding in BHR was higher than that in normotensive control Wistar-Kyoto rats. Pregnanolone, a neuroactive steroid that has been reported to be a putative endogenous modulator in the stress response, concentration dependently enhanced [³H]flunitrazepam binding to the receptor. Enhancement of [³H]flunitrazepam binding was observed to be potentiated by the same immobilized stress, and the EC₅₀ values of pregnanolone in BHR was significantly lower than those in controls and E _max values were higher. From the above results, it can be concluded that neural modulation to behavioral stress, especially in GABAergic neurotransmission, is exaggerated in BHR. We propose strain-specific differences of stress reactivity as an important pathogenetic factor in psychosomatic disorders including stress-induced hypertension. This is supported by reports showing exaggerated cardiovascular and symathoadrenal responses to stress in BHR.
关键词：borderline-hypertensive rat;behavioral stress;benzodiazepine receptor;neuroactive steroid