Immobilization stress and prolactin secretion in male rats. Possible roles of dopamine and TRH.
Immobilization stress and prolactin secretion in male rats. Possible roles of dopamine and TRH.
复制标题
雄性大鼠的固定应激和催乳素分泌。
作者：
M. Kawakami;T. Higuchi;M. Matsuura
固定应激对血清催乳素水平有双相效应：雄性大鼠早期的短刺激相，随后是长抑制相。应激诱导血清催乳素升高，而血清TSH水平下降，在固定300分钟。其他应激源，乙醚吸入或福尔马林皮下注射。注射，或TSH静脉注射，这是有效的对照未能提高血清催乳素后300分钟的固定。应激后血清TSH对TRH也有反应。多巴胺受体阻断剂匹莫齐特可使应激大鼠和对照大鼠血清催乳素水平升高。在pimozide预处理的大鼠，血清催乳素水平升高下降，在10分钟的固定，并返回到preimmobilization水平，此后高于那些在没有pimozide治疗应激动物。提示TRH不是应激催乳素释放的生理性PRF，免疫应激可能激活多巴胺能系统，导致垂体催乳素释放活性降低。
Immoblization stress had a biphasic effect on serum prolactin levels: the early short stimulatory phase followed by a long inhibitory phase in male rats. Stress induced the rise in serum prolactin without concomitant increase in serum TSH levels which declined during the immoblization for 300 min. Other stressors, ether inhalation or formalin s.c. injection, or TSH i.v. injection, which were effective in controls failed to elevate serum prolactin after the 300-min immobilization. Serum TSH responded to TRH after the stress as well. Pimozide, dopamine receptor blocker, was effective in increase of serum prolactin in the stressed rats as well as in controls. In pimozide pretreated rats, elevated serum prolactin levels decrease in 10 min by the immobilization and returned to the preimmobilization levels thereafter which were higher than those in stressed animals without pimozide treatment. It is suggested that TRH is not a physiological PRF in the stress-induced prolactin release and that the dopaminergic system may be activated by the immunoblization stress, resulting in decrease of the prolactin-releasing activity of the pituitary.