Atipamezole changes the antinociceptive effects of butorphanol after medetomidine-ketamine anaesthesia in rats.
OBJECTIVE
To investigate the effects of atipamezole administered before butorphanol, on tail-flick latency (TFL) and also following medetomidine-ketamine anaesthesia in rats.


METHODS
Prospective, randomized experimental study.


METHODS
Thirty-four adult male Sprague-Dawley rats weighing 260-390 g.


METHODS
TFL in 50 degrees C water was used to measure antinociception. In the first experiment, rats received saline (n = 5) or atipamezole (n = 5) followed by butorphanol treatments. In the second experiment, three groups of rats received saline (n = 8), atipamezole (n = 8) or atimpamezole (n = 8) followed by butorphanol 60 minutes after medetomidine-ketamine administration.


RESULTS
In the first experiment, butorphanol significantly increased TFL compared to baseline. Atipamezole significantly decreased this effect. In the second experiment, TFL was significantly increased after recovery from medetomidine-ketamine anaesthesia compared to baseline. This was almost completely blocked by atipamezole. Atipamezole with butorphanol after recovery from the anaesthesia significantly reduced TFL compared to saline but still significantly increased TFL compared to the baseline.


CONCLUSIONS
Atipamezole attenuated the analgesic effects of butorphanol. When postoperative atipamezole is used to hasten recovery from anaesthesia in rats, it may interfere with the postoperative analgesic effect of butorphanol.
Jang
Hwan Soo
HS
Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, Korea.
Lee
Maan Gee
MG
D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology; D000778:Anesthetics, Dissociative / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D002077:Butorphanol / Q000008:administration & dosage / Q000494:pharmacology*; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology*; D007649:Ketamine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D020926:Medetomidine / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000316:Adrenergic alpha-Agonists; D000701:Analgesics, Opioid; D000778:Anesthetics, Dissociative; D007093:Imidazoles; C050701:atipamezole; D007649:Ketamine; D020926:Medetomidine; D002077:Butorphanol