| dc.description.abstract | Nine rabbits were studied after injection intramuscularly with xylazine¹ (8mg/kg) and ketamine² (50mg/kg). Twenty minutes later, rabbits received intravenous injections of yohimbine³ (0.5mg/kg), tolazoline⁴(6.6mg/kg), or physiological saline (0.5ml). Treatments were randomized according to Latin square design and at least seven days were allowed between treatment in each rabbit. Recordings were taken at ten-minute intervals for 80 minutes. Mean time to sternal recumbency (as measured from time of injection of reversal drugs or saline) was significantly shortened to 91±21 minutes with yohimbine and 83±19 minutes with tolazoline as compared to 117±13 minutes with saline. Though not statistically significant (p≤.05), mean time to standing (128±40 minutes for yohimbine, 114±23 minutes for tolazoline, 134i17 minutes for saline), mean time to walking (128±44 minutes for yohimbine, 111±27 minutes for tolazoline, 142:11 minutes for saline), and mean time to walking with full coordination (150±37 minutes for yohimbine, 142±23 minutes for tolazoline, 187±60 minutes for saline) were shortened with both drugs as compared to saline. Relapses to unconsciousness did not occur. Palpebral and withdrawal- responses returned much more rapidly with yohimbine than with the other two drugs. These responses returned more quickly with tolazoline than with saline. 'Heart rates were highest after yohimbine. In all three groups, heart rates were significantly different from each other. Respiratory rates, though not significant, were higher with yohimbine and tolazoline than with saline. Though both yohimbine and tolazoline were effective for reversing xylazine-ketamine anesthesia in rabbits at the dosages given, tolazoline provided the most desirable recovery. Both antagonists, however, would be useful for enhancing arousal in xylazine-ketamine depressed rabbits. | en |
