Yamaguchi K, Hama H
Department of Physiology, Niigata University School of Medicine, Japan.
Brain Res. 1991 Sep 20;559(2):261-6. doi: 10.1016/0006-8993(91)90010-s.
The aim of this study was to evaluate periventricular dopaminergic and alpha-adrenergic receptor functions in vasopressin (AVP) secretion elicited by central applications of prostaglandin D2 (PGD2) in conscious rats. Intracerebroventricular (i.c.v.) injections of PGD2 (70.9 nmol (25.0 micrograms] produced transient rises in plasma AVP 5 min later, without increasing plasma osmolality, sodium and hematocrit. Arterial pressure and heart rate before and after the PGD2 administrations were not significantly different from those of control rats receiving its vehicle. The PGD2-induced AVP response was not significantly altered by the prior i.c.v. administrations (0.15 mumol) of dopamine receptor antagonists, SCH 23390 or sulpiride, and an alpha-adrenoreceptor antagonist, phenoxybenzamine, performed 10 min before the injections of PGD2. The pretreatments with these catecholamine antagonists were confirmed to significantly prevent the augmentations in plasma AVP 5 min after the i.c.v. applications of 0.75 mumol dopamine or phenylephrine that were considerably larger than the PGD 2-induced AVP response. From these results, we concluded that dopaminergic and alpha-adrenergic receptors in the periventricular regions may not be involved in the AVP secretion stimulated by PGD2.
本研究旨在评估清醒大鼠中，脑室周围多巴胺能和α-肾上腺素能受体在前列腺素D2（PGD2）中枢给药引发的血管加压素（AVP）分泌中的作用。脑室内（i.c.v.）注射PGD2（70.9 nmol（25.0微克））5分钟后可使血浆AVP短暂升高，而不增加血浆渗透压、钠和血细胞比容。PGD2给药前后的动脉血压和心率与接受其赋形剂的对照大鼠无显著差异。在注射PGD2前10分钟进行的脑室内多巴胺受体拮抗剂SCH 23390或舒必利以及α-肾上腺素能受体拮抗剂酚苄明（0.15 μmol）的预先给药，并未显著改变PGD2诱导的AVP反应。这些儿茶酚胺拮抗剂的预处理被证实可显著阻止脑室内注射0.75 μmol多巴胺或去氧肾上腺素5分钟后血浆AVP的升高，其升高幅度远大于PGD2诱导的AVP反应。从这些结果来看，我们得出结论，脑室周围区域的多巴胺能和α-肾上腺素能受体可能不参与PGD2刺激的AVP分泌。
