Guard C, Schwark W, Kelton D, Dobson A
Department of Clinical Sciences, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853.
Cornell Vet. 1988 Jan;78(1):89-98.
Rate and amplitude of contractions of the rumen dorsal sac and reticulum of 6 male Holstein calves ages 12 to 20 weeks were monitored with electromyography, strain gauges and an intraruminal pressure catheter. Heart rate and mean arterial pressure were measured with ultrasound. The effects of metoclopramide, a dopamine antagonist, clenbuterol, a beta-2 adrenergic agonist, and butorphanol, a narcotic agonist/antagonist, were observed utilizing dosages bracketing those employed clinically. Metoclopramide significantly decreased the intraruminal pressure peaks associated with cyclical contractions without changing their rate. Clenbuterol had no measurable effect on the ruminoreticulum. Butorphanol totally inhibited ruminoreticular contractions for periods of 6 to greater than 40 min depending on dosage. Only clenbuterol significantly affected cardiovascular function; it increased heart rate and decreased mean arterial pressure. Both metoclopramide and butorphanol produced behavioral changes in the calves.
使用肌电图、应变片和瘤胃内压力导管监测了6头12至20周龄雄性荷斯坦犊牛瘤胃背囊和网胃的收缩速率及幅度。通过超声测量心率和平均动脉压。观察了多巴胺拮抗剂甲氧氯普胺、β-2肾上腺素能激动剂克伦特罗和麻醉性激动剂/拮抗剂布托啡诺的作用，使用的剂量与临床用药剂量相当。甲氧氯普胺显著降低了与周期性收缩相关的瘤胃内压力峰值，但未改变其速率。克伦特罗对瘤胃-网胃没有可测量的影响。布托啡诺根据剂量不同，可完全抑制瘤胃-网胃收缩6至超过40分钟。只有克伦特罗显著影响心血管功能；它增加心率并降低平均动脉压。甲氧氯普胺和布托啡诺都使犊牛出现行为变化。
