Zornow M H
Department of Anesthesiology, University of California San Diego, La Jolla 92093.
Neuropharmacology. 1991 Oct;30(10):1065-71. doi: 10.1016/0028-3908(91)90135-x.
Dexmedetomedine is a potent alpha 2 adrenergic agonist which can reduce anesthetic requirements by over 90% in rats and dogs. This study examined the effects of various doses of dexmedetomidine on the following monitored variables in New Zealand white rabbits: arterial blood gases, mean arterial pressure, respiratory rate, heart rate, and level of sedation. Following the percutaneous insertion of arterial and venous catheters, 21 rabbits received an infusion of saline or dexmedetomidine (20, 80 or 320 micrograms/kg). Monitored variables were recorded at 5, 15, 30 and 60 min following the infusion. Dexmedetomidine produced significant dose-dependent increases in PaCO2 and level of sedation. There were significant decreases in heart rate, PaO2 and respiratory rate. There was no significant change in mean arterial pressure even at the highest (320 micrograms/kg) dose. To examine the ability of an alpha 2 adrenergic antagonist to reverse the effects of dexmedetomidine, 5 rabbits initially received 320 micrograms/kg of dexmedetomidine as described above. Seven minutes after completion of the infusion, 900 micrograms/kg of the alpha 2 adrenergic antagonist, idazoxan, was administered. This resulted in a prompt and sustained reversal of the hypercarbia and sedation produced by the dexmedetomidine.
右美托咪定是一种强效的α2肾上腺素能激动剂，在大鼠和犬中可使麻醉需求降低90%以上。本研究考察了不同剂量右美托咪定对新西兰白兔下列监测指标的影响：动脉血气、平均动脉压、呼吸频率、心率和镇静水平。经皮插入动脉和静脉导管后，21只兔接受生理盐水或右美托咪定（20、80或320微克/千克）输注。输注后5、15、30和60分钟记录监测指标。右美托咪定使PaCO2和镇静水平出现显著的剂量依赖性升高。心率、PaO2和呼吸频率显著降低。即使在最高剂量（320微克/千克）时，平均动脉压也无显著变化。为了考察α2肾上腺素能拮抗剂逆转右美托咪定作用的能力，5只兔最初如上所述接受320微克/千克右美托咪定。输注结束7分钟后，给予900微克/千克的α2肾上腺素能拮抗剂咪唑克生。这导致右美托咪定所致的高碳酸血症和镇静作用迅速且持续逆转。
