Rutkowski J A, Eades S C, Moore J N
Section of Surgery, School of Veterinary Medicine, University of Pennsylvania, New Bolton Center, Kennett Square 19348.
Am J Vet Res. 1991 Jul;52(7):1153-8.
A chronic model with an ultrasonic transit time blood flow probe and strain gauge force transducers implanted on the cecum was used to evaluate cecal mechanical activity and cecal arterial blood flow in 4 conscious adult horses. Intravenous administration of xylazine (1.1 mg/kg of body weight) significantly decreased heart rate and cardiac output, but significantly increased diastolic pulmonary arterial pressure, mean pulmonary arterial pressure, carotid arterial pressure, and central venous pressure. Lateral cecal arterial blood flow after xylazine administration was decreased substantially more than was cardiac output, suggesting that xylazine caused constriction of the cecal vasculature. This effect of xylazine may have resulted from either a direct effect of xylazine on the cecal vasculature or from reflex vasoconstriction attributable to reduced cardiac output. Intravenous administration of butorphanol tartrate (0.1 mg/kg) did not significantly alter the hemodynamic responses to xylazine. Cecal mechanical activity, as measured by the motility index, was decreased for 120 minutes after administration of xylazine and for 150 minutes after administration of xylazine/butorphanol.
采用一种慢性模型，将超声渡越时间血流探头和应变片力传感器植入4匹成年清醒马的盲肠，以评估盲肠的机械活动和盲肠动脉血流量。静脉注射甲苯噻嗪（1.1毫克/千克体重）可显著降低心率和心输出量，但显著升高舒张期肺动脉压、平均肺动脉压、颈动脉压和中心静脉压。注射甲苯噻嗪后，盲肠外侧动脉血流量的减少幅度明显大于心输出量的减少幅度，这表明甲苯噻嗪可导致盲肠血管收缩。甲苯噻嗪的这种作用可能是由于甲苯噻嗪对盲肠血管的直接作用，或者是由于心输出量减少引起的反射性血管收缩。静脉注射酒石酸布托啡诺（0.1毫克/千克）并未显著改变对甲苯噻嗪的血流动力学反应。用运动指数衡量，注射甲苯噻嗪后120分钟以及注射甲苯噻嗪/酒石酸布托啡诺后150分钟，盲肠机械活动均降低。
