Asai T, Mapleson W W, Power I
Department of Anaesthetics and Intensive Care Medicine, University of Wales College of Medicine, Cardiff.
Br J Anaesth. 1998 Jan;80(1):63-7. doi: 10.1093/bja/80.1.63.
We studied the interactive effect of dexmedetomidine and morphine on gastric emptying and gastrointestinal transit in the rat. In one group of rats, to examine the interactive effect on gastrointestinal transit, the two drugs were injected i.p. in a fixed ratio (30: 1)--that of their ED50 values--in six doses (0.062-1.075 mg kg-1), each to a different group of 5-8 male rats for each dose. In another group, to examine the interactive effect on gastric emptying, either dexmedetomidine or saline was injected with saline or with the ED25 or ED50 of morphine (0.22 and 2.8 mg kg-1, respectively). In both groups, at 30 min, radiolabelled saline 1 ml was infused into the stomach; at 1 h, gastric emptying or gastrointestinal transit was calculated by measuring the radioactivity in the gastrointestinal tract. Morphine and dexmedetomidine produced a supra-additive inhibitory effect on gastrointestinal transit (P = 0.02). Dexmedetomidine 0.01 mg kg-1, which itself significantly inhibited gastric emptying (P < 0.01), did not significantly alter the inhibitory effect of morphine on gastric emptying. Therefore, in rats, dexmedetomidine markedly enhanced the inhibitory effect of morphine on gastrointestinal transit, but it did not significantly alter the effect on gastric emptying.
我们研究了右美托咪定和吗啡对大鼠胃排空及胃肠转运的交互作用。在一组大鼠中，为检测对胃肠转运的交互作用，将两种药物按固定比例（30:1）——即它们的半数有效剂量（ED50）值的比例——腹腔注射，共六个剂量（0.062 - 1.075毫克/千克），每个剂量分别给予不同组的5 - 8只雄性大鼠。在另一组中，为检测对胃排空的交互作用，右美托咪定或生理盐水分别与生理盐水或吗啡的25%有效剂量（ED25）或50%有效剂量（ED50）（分别为0.22和2.8毫克/千克）一起注射。在两组中，30分钟时，向胃内注入1毫升放射性标记的生理盐水；1小时时，通过测量胃肠道内的放射性来计算胃排空或胃肠转运情况。吗啡和右美托咪定对胃肠转运产生了超相加抑制作用（P = 0.02）。0.01毫克/千克的右美托咪定本身显著抑制胃排空（P < 0.01），但并未显著改变吗啡对胃排空的抑制作用。因此，在大鼠中，右美托咪定显著增强了吗啡对胃肠转运的抑制作用，但对胃排空的作用未产生显著改变。
