Induction of muscarinic acetylcholine, serotonin and substance P receptors in Xenopus oocytes injected with mRNA prepared from the small intestine of rats

Abstract Serotonin and muscarinic acetylcholine (ACh) receptors were clearly induced in Xenopus oocyte injected with mRNA prepared from the small intestines of rats. Their response to ACh and serotonin was composed of 4 distinct components: fast and slow depolarization, slow hyperpolarization and large membrane potential fluctuation. About three-quarters of the injected oocytes responded to substance P. The response of the injected oocytes to substance P was transient and decayed even in the presence of substance P, indicating the presence of desensitization. However, the injected oocytes showed no response to 6 other drugs analyzed: adrenaline, noradrenaline, dopamine, γ-aminobutyric acid, glycine and glutamate.