Heitkemper M M, Bond E F
Department of Physiological Nursing, University of Washington, Seattle.
Biol Neonate. 1990;58(1):8-15. doi: 10.1159/000243225.
The effects of thyrotropin-releasing hormone (TRH) on the contractile activity of the proximal jejunum and distal colon of 3-, 7-, 14-, 21-, 28-, 50-day-old and adult male Sprague-Dawley rats were examined. Longitudinal segments were mounted in force displacement transducers and bathed in oxygenated, buffered Krebs' solution. In the proximal jejunum TRH 10(-6) M produced a tetrodotoxin (TTX)-sensitive tension increase in 3- to 14-day-old rats and a TTX-resistant biphasic response in older rats. TRH 10(-6) M produced a transient tension in the distal colon of rats less than or equal to 21 days old. Incubation with TRH 10(-6) M for 30 min increased responsiveness to acetylcholine 10(-7) M in approximately 50% of tissues studied. Direct and indirect effects of TRH are developmentally determined.
研究了促甲状腺激素释放激素（TRH）对3日龄、7日龄、14日龄、21日龄、28日龄、50日龄成年雄性Sprague-Dawley大鼠空肠近端和结肠远端收缩活性的影响。将纵行肠段安装在力位移换能器上，并置于充氧的、缓冲的 Krebs 溶液中。在空肠近端，10⁻⁶ M 的 TRH 在3至14日龄大鼠中引起对河豚毒素（TTX）敏感的张力增加，而在年龄较大的大鼠中引起对 TTX 抵抗的双相反应。10⁻⁶ M 的 TRH 在21日龄及以下大鼠的结肠远端产生短暂张力。用10⁻⁶ M 的 TRH 孵育30分钟可使约50%的研究组织对10⁻⁷ M 乙酰胆碱的反应性增加。TRH 的直接和间接作用由发育决定。
