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  • ThesisItemOpen Access
    Effect of ephedrine and 4-aminopyridine - yohimbine combination in reversing the ketamine-xylazine anaesthesia in rabbits
    (Department of Pharmacology and Toxicology, College of Veterinary and Animal Sciences, Mannuthy, 1999) Chandra Rajeswari, K; KAU; Chandrashekaran Nair, A M
    An attempt was made to assess the efficacy of ephedrine as a reversing agent in comparison with the known antagonists combination, yohimbine and 4-AP in xylazine-ketamine anaesthesia in rabbits. The study was conducted in thirty two NewZealand White rabbits divided into four groups of eight each. All the four groups (C, Tj , T2 and T3) were anaesthetized with 5 mg/kg xylazine and 50 mg/kg ketamine administered intramuscularlyat 15 min. interval. Group 'C' served as control, groups Tj , T2 and T3 served as treatments. In the middle of anaesthesia i.e., 30 min. after induction of anaesthesia, group T 1 received yohimbine and 4-AP combination (0.125 mg/kg and 0.2 mg/kg respectively IN), group T2 were given ephedrine (10 mg/kg IN) and group T 3 received with ephedrine (20 mg/kg IN). The anaesthetic parameters like the sequence and time of disappearance and reappearance of righting, corneal, palpebral, ear-twitch and hind limb pedal reflexes, duration of anaesthesia, arousal and recovery time were observed for all groups. The rectal temperature, pulse rate and respiration rate were recorded at 0, 5, 10, 20, 30, 45, 60, 75, 90, 120, 150 min. during anaesthesia and also after complete recovery. Haemogram was also studied before, during and also after complete recovery from anaesthesia. The sequence and time of disappearance of reflexes are as follows. Righting reflex was the first to disappear (1.4 min.) followed by hindlimb pedal, corneal, palpebral and ear-twitch reflexes disappeared at 3.7, 4.5 and 4.6 min. respectively after ketamine administration in all the four groups. The mean time for disappearance of aforesaid reflexes showed no significant variation among the different groups as the same anaesthetic schedule was adopted for all the groups. Animals regained consciousness with the onset of Zwangsnagen reflex, followed by reappearance of corneal, palpebral, ear-twitch and hindlimb pedal reflex. Time for appearance of Zwangsnagen, corneal, palpebral and ear-twitch reflexes were significantly reduced in treatment groups when compared to control and there was no significant difference between treatment groups for these parameters. Time for reappearance of hindlimb pedal reflex was significantly shorter for group T3 when compared to groups Tl and In companson with control group (60.6 min.) the mean duration of anaesthesia was significantly reduced for treatment groups Tb T2 and T3 (33.6, 34.2 and 31.1 min. respectively). This decrease was significantly greater in T3 when compared to T 1 and T 2. Statistical analysis showed no significant di fference between T 1 and T 2 in duration of anaesthesia. All the four groups differ significantly from each other in the arousal and recovery time. Shortest arousal time was recorded in T 1 group (9.1 min.) followed by T3 (21.3 min.) and T2 (35.5 min.). Arousal time in control group was 103.85 min. The duration of time taken for recovery was greater for control group (86.9 min.) followed by groups Tl and T2 (65.4 and 56.0 min. respectively). These values were found to be significantly shorter for the group T 3 (41.5 min.). The rectal temperature, pulse and respiration rates were significantly decreased below normal values during xylazine-ketamine anaesthesia. These parameters were found to be increased significantly after administration of reversing agents in all treatment groups when compared to control group. The study of haemogram showed that Hb, PC V, total RBC and total leucocyte counts were significantly decreased during anaesthesia. These haematological changes were completely reversed by administration of reversing agents in treatment groups. From the results of the present study it could be concluded that ephedrine can be used as an alternative to yohimbine and 4-AP combination in reversing the anaesthesia produced by xylazine-ketamine combination in rabbits.