静松灵和隆朋对驴胃收缩增强和抑制的双相作用及其机理的研究

THE BIPHASIC EFFECTS OF XYLIDINOTHIAZOLE AND XYLAZINE ON THE CONTRACTION OF THE DONKEY STOMACH

微型气囊法监测驴胃蠕动压和基础胃内压。静松灵0.15mg/kg i.v.引起驴胃蠕动增强了23.25±6.02分钟(n=4),并表现成Ⅰ、Ⅱ、Ⅲ期运动规律,育亨宾0.30mg/kg i.v.可以使静松灵的作用时间缩短到12.25±2.70分(n=4),有显著的拮抗作用(P<0.05);而静松灵0.50mg/kg i.v.使胃蠕动抑制了18.27±2.42分钟(n=5),然后使胃蠕动增强13.25±6.08分钟,也引起兴奋-抑制-兴奋的Ⅰ、Ⅱ、Ⅲ期变化规律,妥拉苏林能极显著地拮抗静松灵0.50mg/kg i.v.对胃的抑制(P<0.01),立即使胃蠕动增强了15.84±4.00分钟(n=3)。隆朋也有较弱的双相现象。实验表明,药物对驴胃的兴奋和抑制的双相作用,是分别激动在中枢的Alpha-2肾上腺素受体的突触后受体和突触前受体。临床使用这类化学保定药时,应考虑它对马属动物的双相作用。

The peristalsis and base-line pressure were monitored with a miniature balloon in the donkey stomach. Administration of low dosage of Xylidinothiazole ( 0.15mg/kg of body weight i.v ) increased phasic contractions of stomach for 23.25 ±6.02minutes (n= 5).The time-response relationship of phasic contraction was apparently divided into Ⅰ , Ⅱ and Ⅲ phases during the drug affecting period. Yohimbine ( 0.3mg/kg of body weight i.v) significantly decreased the amplitude of contraction and shorten the time-effect induced by Xylidinothiazole (P<0.05) .In the presence Xylidinothiazole at high dosage of 0.50mg/kg of body weight ( i.v ) , peristalsis also appeared to: phase Ⅰ , immediately contract stronger for the short time than before administration; and then phase ?Ⅱ be vanished by the drug for 18.27± 2.43 minutes, which were significantly antagonized with tolazoline (2.5mg/kg i.v) ( P<0.01 ) ;In the last phase increase phasic contraction of peristalsis once again for 13.25±6.08 minutes. The biphasic effects of Xylazine were much lower than Xylidinothiazole. The results indicate that the drug mediated both post and pre-synapis of alpha-2 adrenoceptor which may respectively increased or decreased contraction of the stomach biphasic peristalsis according to dosage-effect and time-response relationship. It is also suggested that the drug receptor in olved in the central nervous system by indrect action on the donkey stomach.