Fox J E, McDonald T J, Kostolanska F, Tatemoto K
Life Sci. 1986 Jul 14;39(2):103-10. doi: 10.1016/0024-3205(86)90443-1.
Galanin injected intraarterially during phasic activity of the canine small intestine in vivo produced inhibition. Fifty percent inhibition occurred at 1.5 +/- 0.5 X 10(-10) mols lasting for 0.7 min. The inhibitory response was not decreased by treatment with atropine, hexamethonium, yohimbine or naloxone, suggesting that muscarinic, nicotinic, alpha 2 adrenergic or opiate receptors were not being stimulated. Since tetrodotoxin blockade of nerves did not reduce the response and galanin at 10(-10) mols was able to eliminate the smooth muscle response to intraarterial acetylcholine, we suggest that galanin acts to inhibit smooth muscle directly. Galanin 10(-9) M added to the muscle bath also inhibited phasic activity of the canine ileum circular muscle in vitro in the presence of tetrodotoxin. These results suggest that the neural peptide galanin may be a non-adrenergic, non-cholinergic, non-opioid neurotransmitter in the canine small intestine.
在犬小肠体内的阶段性活动期间动脉内注射甘丙肽会产生抑制作用。在1.5±0.5×10⁻¹⁰摩尔时出现50%的抑制，持续0.7分钟。用阿托品、六甲铵、育亨宾或纳洛酮处理后，抑制反应并未减弱，这表明毒蕈碱、烟碱、α₂肾上腺素能或阿片受体未被刺激。由于用河豚毒素阻断神经并未降低反应，且10⁻¹⁰摩尔的甘丙肽能够消除平滑肌对动脉内乙酰胆碱的反应，我们认为甘丙肽直接作用于平滑肌以产生抑制。在存在河豚毒素的情况下，向肌肉浴中添加10⁻⁹摩尔的甘丙肽也会抑制犬回肠环行肌的体外阶段性活动。这些结果表明，神经肽甘丙肽可能是犬小肠中的一种非肾上腺素能、非胆碱能、非阿片类神经递质。
