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Effect of intracerebro-ventricular microinjection of pentagastrin on gastrointestinal propulsive motility in the rat

Li Xicheng, Zhang Changcheng, Pan Xijuan, Liu Shengtian, Zhou Zonghui

Department of physiology, Third Medical College of PLA. Chongqing, China；Department of Physiology, Zunyi Medical College. Quizhou, China

Abstract

The purpose of this study is to observe the effect of intracerebroventricular (ICV) microinjection of pentagastrin(吼)on gastrointestinal propulsive . motility in the rat. The distance travelled by the charcol meal through the small intestine measured in terms of percentage of its total length was taken as the index of gastrointestinal propulsive motility. The results were as follows: (1) Injection of G_(5)(1 #mu#g/10 #mu#l, 2 #mu#g/10 #mu#l or 4 #mu#g/10 #mu#l) into the cerebro-ventricle significantly strengthened the gastrointestinal propulsive motility (P<0.01-0.001). These effects were abolished by vagotomy or by injection of atropine into the hypoderm (0.2 mg/kg) or into the cerebro-ventricle (5 #mu#g/10 #mu#l). (2) The gastrointestinal propulsive motility inceased markedly (P<0.001) after injection of a larger dose of G_(2) (20 #mu#g/1OOg) into the muscle. These effects were completely blocked by subcutaneous injection of atropine (0.2 mg/100g) (P<0.001). (3) No effects (P>0.05) were found in the gastrointestinal propulsive motility after intramuscular or intracerebro-ventricular injection of regitine (2.5 mg/kg im, 50 #mu#g/10 #mu#l ICV) or propranolol (5 mg/kg im, 50 #mu#g/50 #mu#l ICV). These results indicate that intracerebro-ventricular administration of G_(6) acts initially on certain cholinergic system, the enhanced activity of which is mediated by vagal nerve to cause some increase of gastrointestinal propulsive motility.

Key words: Pentagastrin (G_(5));Cerebro-ventricle;Microinjection;Gastrointestinal propulsive motility;Vagal nerve;Atropine

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Citing This Article：

Li Xicheng, Zhang Changcheng, Pan Xijuan, Liu Shengtian, Zhou Zonghui. Effect of intracerebro-ventricular microinjection of pentagastrin on gastrointestinal propulsive motility in the rat. Acta Physiol Sin 1985; 37 (3): (in Chinese with English abstract).