降钙素对中枢神经系统的作用：对大鼠催乳素释放的刺激作用

Central nervous system effect of calcitonin: stimulation of prolactin release in rats.

作者信息

Chihara K, Iwasaki J, Iwasaki Y, Minamitani N, Kaji H, Fujita T

出版信息

Brain Res. 1982 Sep 30;248(2):331-9. doi: 10.1016/0006-8993(82)90591-1.

Abstract

Effect of [Asu 1,7]eel calcitonin (CT) on prolactin (PRL) release was examined in male rats under urethane anesthesia. Intravenous injection of 4-20 micrograms [Asu1,7]eel CT did not modify plasma PRL levels. Injections of 0.5-2.5 micrograms [Asu1,7]eel CT into the lateral ventricle produce a significant and dose-related increase of plasma PRL within 10 min of injection. When intraventricularly injected in an equimolar dose (0.74 nmol/10 microliters), eel CT11-32, eel CT15-32, [Asu1,7]eel CT1-16 and [Asu1,7]eel CT1-9 showed 44.8, 25.7, 19.9 and 10.1% the potencies of [Asu1,7]eel CT, respectively, in stimulating activity of PRL release. The rise of plasma PRL after [Asu1,7]eel CT injection were significantly less or abolished not only in hypothalamic-lesioned rats but also in rats with complete deafferentation. Pretreatment with alpha-methyl-p-tyrosine (250 mg/kg, 12 h before) but not with p-chlorophenylalanine (300 mg/kg, 72 and 24 h before) resulted in a suppression of [Asu1,7]eel CT-induced PRL release. These results suggest the following: first, PRL release is stimulated by centrally injected [Asu1,7]eel CT, the action site of which may exist in the extrahypothalamic area; second, brain catecholamines may be involved in the mechanism of [Asu1,7]eel CT-evoked PRL release; third, the C-terminal portion of the peptide may play an important role in stimulating PRL release.

摘要

在氨基甲酸乙酯麻醉下，研究了[Asu 1,7]鳗鱼降钙素（CT）对雄性大鼠催乳素（PRL）释放的影响。静脉注射4 - 20微克[Asu1,7]鳗鱼CT不会改变血浆PRL水平。向侧脑室注射0.5 - 2.5微克[Asu1,7]鳗鱼CT会在注射后10分钟内使血浆PRL显著且呈剂量相关地增加。当以等摩尔剂量（0.74纳摩尔/10微升）脑室内注射时，鳗鱼CT11 - 32、鳗鱼CT15 - 32、[Asu1,7]鳗鱼CT1 - 16和[Asu1,7]鳗鱼CT1 - 9在刺激PRL释放活性方面分别显示出[Asu1,7]鳗鱼CT效力的44.8%、25.7%、19.9%和10.1%。[Asu1,7]鳗鱼CT注射后血浆PRL的升高不仅在下丘脑损伤的大鼠中显著降低或消除，在完全去传入神经的大鼠中也是如此。用α-甲基-对-酪氨酸（250毫克/千克，提前12小时）预处理可抑制[Asu1,7]鳗鱼CT诱导的PRL释放，但用对氯苯丙氨酸（300毫克/千克，提前72小时和24小时）预处理则无此作用。这些结果表明：第一，脑室内注射[Asu1,7]鳗鱼CT可刺激PRL释放，其作用位点可能存在于下丘脑外区域；第二，脑儿茶酚胺可能参与[Asu1,7]鳗鱼CT诱发PRL释放的机制；第三，该肽的C末端部分在刺激PRL释放中可能起重要作用。