Exogenous opiates: their local mechanisms of action in the canine small intestine and stomach.
Exogenous opiates: their local mechanisms of action in the canine small intestine and stomach.
复制标题
外源性阿片类药物：它们在犬小肠和胃中的局部作用机制。
DOI：
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发表时间：
1987
影响因子：
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通讯作者：
E. Daniel
中科院分区：
文献类型：
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作者：
J. Fox;E. Daniel
将甲硫氨酸脑啡肽(Met-Enk)和强啡肽分别动脉注射到麻醉犬远端胃和小肠的静止期和由场刺激或动脉注射胃动素引起的时相活动。同时观察了吗啡、[D-Ala2，N-Me-Phe4，Met(O)5-ol]脑啡肽(Met-ol)和[D-Ala2，D-Leu5]脑啡肽(DADLE)的作用。阿片类药物对静止的胃没有影响，但对时相收缩有抑制作用(效力：强啡肽大于Met-Enk大于Met-ol大于DADLE大于吗啡)。在静止的小肠中，除强啡肽外，小剂量的每种阿片剂都产生兴奋(效力：Met-Enk与Met-Enk一致，Met-ol与DADLE一致，大于吗啡)。兴奋显然是通过释放乙酰胆碱和部分对纳洛酮敏感的直接刺激平滑肌来实现的。在时相活动期间，所有阿片类药物都能抑制时相肌肉收缩(相对效力如胃)。强啡肽对胃和小肠的抑制作用是通过纳洛酮敏感地抑制神经释放乙酰胆碱而发生的。因此，阿片剂对胃和小肠的抑制似乎是常见的，而兴奋只在小肠中是阿片类药物作用的一种功能。强啡肽可能是一种引起抑制的天然神经肽，Met-Enk可能是一种引起兴奋的天然神经肽。
Methionine-enkephalin (Met-Enk) and dynorphin were injected intra-arterially into the distal stomach and small intestine of the anesthetized dog during quiescence and phasic activity initiated by field stimulation or intra-arterially administered motilin. The effects of morphine, [D-Ala2, N-Me-Phe4, Met(O)5-ol]enkephalin (Met-ol), and [D-Ala2, D-Leu5]enkephalin (DADLE) were also examined. Opiates had no effect on the quiescent stomach but produced inhibition of phasic contractions (potencies: dynorphin greater than Met-Enk greater than Met-ol greater than DADLE greater than morphine). In the quiescent small intestine, low doses of each opiate, except dynorphin, produced excitation (potencies: Met-Enk congruent to Met-ol congruent to DADLE greater than morphine). Excitation apparently occurred via release of acetylcholine and a partially naloxone-sensitive direct stimulation of smooth muscle. During phasic activity all opiates produced inhibition of phasic muscular contractions (relative potencies as in the stomach). Inhibition by dynorphin in both the stomach and small intestine was shown to occur via naloxone-sensitive inhibition of release of acetylcholine from nerves. Thus inhibition by opiates appears common to the stomach and small intestine, and excitation is a function of opiate action only in the small intestine. Dynorphin may be a natural neuropeptide causing inhibition, and Met-Enk may be a natural neuropeptide causing excitation.