Guo A L, Petraglia F, Criscuolo M, Ficarra G, Nappi R E, Palumbo M A, Trentini G P, Purdy R H, Genazzani A R
Department of Obstetrics and Gynecology, University of Pisa, Italy.
Gynecol Endocrinol. 1995 Mar;9(1):1-7. doi: 10.3109/09513599509160184.
The neurosteroid allopregnanolone has been shown to be a potent ligand of gamma-aminobutyric acid (GABA)-A receptors and enhances its receptor-mediated inhibitory events. Since central GABA plays a major inhibitory role, via GABA-A receptors, in hypothalamic-pituitary-adrenal (HPA) function in rats, the present study has evaluated the effect of passive immunoneutralization of allopregnanolone on diurnal changes in corticosterone secretion and acute stress-induced corticosterone secretion in rats. In the first protocol, four groups of male rats (prepubertal, fertile, castrated adult and aged) and three groups of female rats (prepubertal, fertile at different phases of the estrous cycle and aged) were studied. Rats were injected intracerebroventricularly (i.c.v.) with 10 microliters anti-allopregnanolone serum or 10 microliters normal rabbit serum (control) 24 h before exposure to an acute cold swimming stress, and sacrificed either before stress or after 5 min stress. In the second protocol, fertile male or female rats at diestrus II were injected i.c.v. with anti-allopregnanolone serum or normal rabbit serum and sacrificed on the following day at 10.00 or 18.00. Truncal blood samples were collected for measuring plasma corticosterone. Our results showed that there was no significant difference in basal plasma corticosterone levels between antiserum-treated and control rats of both sexes. However, in male rats, central injection of antiserum to allopregnanolone significantly potentiated plasma corticosterone response to stress in prepubertal and adult fertile rats as well as in castrated rats. Likewise, in female rats, the stress response of plasma corticosterone was enhanced by passive immunoneutralization of allopregnanolone in prepubertal and fertile rats throughout the estrous cycle.(ABSTRACT TRUNCATED AT 250 WORDS)
神经甾体别孕烯醇酮已被证明是γ-氨基丁酸（GABA）-A受体的有效配体，并增强其受体介导的抑制作用。由于中枢GABA通过GABA-A受体在大鼠下丘脑-垂体-肾上腺（HPA）功能中起主要抑制作用，本研究评估了别孕烯醇酮被动免疫中和对大鼠皮质酮分泌昼夜变化及急性应激诱导的皮质酮分泌的影响。在第一个实验方案中，研究了四组雄性大鼠（青春期前、可育、去势成年和老年）和三组雌性大鼠（青春期前、处于发情周期不同阶段的可育和老年）。在暴露于急性冷水游泳应激前24小时，给大鼠脑室内注射10微升抗别孕烯醇酮血清或10微升正常兔血清（对照），在应激前或应激5分钟后处死。在第二个实验方案中，给处于动情周期二期的可育雄性或雌性大鼠脑室内注射抗别孕烯醇酮血清或正常兔血清，并于次日上午10:00或下午18:00处死。采集躯干血样本测定血浆皮质酮。我们的结果表明，抗血清处理组和对照组大鼠的基础血浆皮质酮水平无显著差异。然而，在雄性大鼠中，向别孕烯醇酮注射抗血清可显著增强青春期前、成年可育大鼠以及去势大鼠对应激的血浆皮质酮反应。同样，在雌性大鼠中，别孕烯醇酮的被动免疫中和增强了青春期前和整个发情周期可育大鼠血浆皮质酮的应激反应。（摘要截断于250字）
