Wong C L
Methods Find Exp Clin Pharmacol. 1986 Dec;8(12):715-9.
In mice, clonidine administered subcutaneously caused a dose-dependent inhibition of the intestinal motility as assayed by the movement of a charcoal meal. This inhibitory effect of clonidine was antagonized dose-dependently by prior subcutaneous or intracisternal administration of yohimbine. However, yohimbine given intracerebroventricularly was ineffective in antagonising the intestinal inhibitory action of clonidine. Clonidine administered centrally, either intracisternally or intracerebroventricularly, caused a dose-dependent inhibition of intestinal motility. Clonidine given by the intracisternal route appeared to be more effective than by the intracerebroventricular route. Centrally administered clonidine was antagonized by prior subcutaneous administration of yohimbine. The antagonism was related to the doses of yohimbine given. Subcutaneously administered morphine caused a dose-dependent inhibition of intestinal motility and this effect was antagonized by prior subcutaneous administration of yohimbine. However, administration of yohimbine centrally, either intracisternally or intracerebroventricularly, did not affect the intestinal inhibitory action of morphine. On the other hand, morphine injected centrally, either intracisternally or intracerebroventricularly, dose-dependently inhibited the motility of the intestine; such inhibitory action was antagonized by prior subcutaneous administration of yohimbine. The present study suggests that clonidine inhibits intestinal motility at both central and peripheral sites through alpha 2-adrenoceptors. Morphine also inhibits intestinal motility by both central and peripheral mechanisms but it appears that yohimbine only modifies the peripheral aspect of morphine's action.
在小鼠中，皮下注射可乐定可导致肠道运动受到剂量依赖性抑制，这通过炭末餐的移动来测定。可乐定的这种抑制作用可被预先皮下或脑池内注射育亨宾剂量依赖性地拮抗。然而，脑室内注射育亨宾对拮抗可乐定的肠道抑制作用无效。脑池内或脑室内中枢给予可乐定可导致肠道运动受到剂量依赖性抑制。脑池内给予可乐定似乎比脑室内给予更有效。预先皮下注射育亨宾可拮抗中枢给予的可乐定。这种拮抗作用与育亨宾的给药剂量有关。皮下注射吗啡可导致肠道运动受到剂量依赖性抑制，且这种作用可被预先皮下注射育亨宾拮抗。然而，脑池内或脑室内中枢给予育亨宾并不影响吗啡的肠道抑制作用。另一方面，脑池内或脑室内中枢注射吗啡可剂量依赖性地抑制肠道运动；这种抑制作用可被预先皮下注射育亨宾拮抗。本研究表明，可乐定通过α2肾上腺素能受体在中枢和外周部位均抑制肠道运动。吗啡也通过中枢和外周机制抑制肠道运动，但似乎育亨宾仅改变吗啡作用的外周方面。
