Komissarov I V, Reutskaia G I
Biull Eksp Biol Med. 1978 Feb;85(2):180-2.
Dopamine and phenylephrine decreased the tone of the smooth muscles of the isolated rat stomach strips in concentractions of 10(-6) M and higher. The curves of the concentration-effect have the same slope. Dopamine effects are unchanged in the presence of propranolole (5.10(-6) g/ml). Phentholamine (as well as dihydroergotamine and tropaphen) shows an equal degree of antagonism towards both phenylephrine and dopamine. It is suggested that dopamine and phenylephrine relax the stomach muscles by influencing the alpha-adrenoreceptors. The latter differe from alpha-adrenoreceptors of the ejaculatory duct of rats by a high sensitivity to the blocking influence of some neuroleptics--haloperidol, trifluoperazine, chlorpromazine, pA2 for which (8.11--8.64) is of the same range as pA2 for alpha-adrenolytic drugs (7.76--8.46). The features of resemblance and difference between alpha-adrenoreceptors of the gastrointestinal tract muscles and the inhibitory dopamine receptors of the nerve cells are being discussed.
多巴胺和去氧肾上腺素在浓度为10（-6）M及更高时可降低离体大鼠胃条平滑肌的张力。浓度-效应曲线具有相同的斜率。在普萘洛尔（5×10（-6）g/ml）存在的情况下，多巴胺的作用不变。酚妥拉明（以及双氢麦角胺和托拉唑啉）对去氧肾上腺素和多巴胺均表现出同等程度的拮抗作用。提示多巴胺和去氧肾上腺素通过影响α-肾上腺素能受体使胃肌松弛。后者与大鼠射精管的α-肾上腺素能受体不同，对某些抗精神病药物——氟哌啶醇、三氟拉嗪、氯丙嗪的阻断作用高度敏感，其pA2值（8.11 - 8.64）与α-肾上腺素能阻断药物的pA2值（7.76 - 8.46）处于相同范围。正在讨论胃肠道肌肉的α-肾上腺素能受体与神经细胞的抑制性多巴胺受体之间异同的特点。
