Furukawa K, Nomoto T, Tonoue T
Eur J Pharmacol. 1980 Jun 27;64(4):279-87. doi: 10.1016/0014-2999(80)90235-6.
Thyrotropin-releasing hormone (TRH) produced a contraction in the isolated segment of duodenum and taenia coli of the guinea-pig (pA2, 8.0 and 8.9). TRH induced a contraction, a relaxation, or a contraction followed by relaxation in the jejunum and ileum. All the responses to TRH of the small intestine and the taenia coli were abolished in the presence of tetrodotoxin but not affected by hexamethonium. The contractile response to TRH of the small intestine was abolished and replaced by a relaxation in the presence of hyoscine. This relaxant response was not affected by guanethidine. The taenial response to TRH was partially inhibited by either hyoscine or methysergide and markedly diminished by the two together. These findings indicate that TRH acts on the myenteric neurons of the small intestine and taenia coli of the guinea pig. The contractile response of small intestine is likely to be induced through cholinergic nerves while cholinergic, serotonergic and unidentified excitatory neurons seem to be involved in the taenial response. These neurogenic actions of TRH on the guinea-pig intestine are in contrast with the myogenic natur of the response to TRH in the duodenum of the rat.
促甲状腺激素释放激素（TRH）可使豚鼠十二指肠和结肠带的离体节段产生收缩（pA2分别为8.0和8.9）。TRH可使空肠和回肠产生收缩、舒张或先收缩后舒张。小肠和结肠带对TRH的所有反应在存在河豚毒素时均被消除，但不受六甲铵影响。在存在东莨菪碱时，小肠对TRH的收缩反应被消除并被舒张所取代。这种舒张反应不受胍乙啶影响。结肠带对TRH的反应可被东莨菪碱或甲基麦角新碱部分抑制，二者共同作用时则明显减弱。这些发现表明，TRH作用于豚鼠小肠和结肠带的肌间神经元。小肠的收缩反应可能是通过胆碱能神经诱导的，而胆碱能、5-羟色胺能和未确定的兴奋性神经元似乎参与了结肠带的反应。TRH对豚鼠肠道的这些神经源性作用与大鼠十二指肠对TRH反应的肌源性性质形成对比。
