Milenov K, Rakovska A, Bocheva A, Vassileva M
Institute of Physiology, Bulgarian Academy of Sciences.
Acta Physiol Pharmacol Bulg. 1987;13(3):66-74.
Mechanical activity was recorded from muscle preparations isolated from the guinea-pig stomach. Neurotensin (10(-11) M to 10(-7) M) produced dose-dependent tonic contractions and showed a higher affinity but lower efficiency compared to acetylcholine (ACH). Atropine and tetrodotoxin had no effect on the neurotensin responses. Blockade of prostaglandin (PG) synthesis by indomethacin or cortisone (5 X 10(-6) M) shifted to the right the dose-response curve for neurotensin (NT) and significantly reduced the NT maximum responses. The data suggest the involvement of PG-mechanisms in the myogenic effect of neurotensin. The electrically-induced, atropine-sensitive contractions (5 to 10 Hz, 0.3 to 0.5 ms) of the muscle strips were inhibited by NT (10(-11) M to 10(-9) M). This inhibition was overcome by yohimbine (10(-6) M) or prostaglandin F2a. It is concluded that NT modulates cholinergic neurotransmission in gastric smooth muscle probably via presynaptically located adrenoceptors.
从豚鼠胃分离的肌肉标本记录机械活动。神经降压素（10⁻¹¹ M至10⁻⁷ M）产生剂量依赖性强直收缩，与乙酰胆碱（ACH）相比，显示出更高的亲和力但效率更低。阿托品和河豚毒素对神经降压素反应无影响。吲哚美辛或可的松（5×10⁻⁶ M）阻断前列腺素（PG）合成使神经降压素（NT）的剂量反应曲线右移，并显著降低NT最大反应。数据表明PG机制参与神经降压素的肌源性效应。肌肉条带的电诱导、阿托品敏感收缩（5至10 Hz，0.3至0.5 ms）被NT（10⁻¹¹ M至10⁻⁹ M）抑制。育亨宾（10⁻⁶ M）或前列腺素F2α可克服这种抑制。结论是NT可能通过突触前定位的肾上腺素能受体调节胃平滑肌中的胆碱能神经传递。
