Volume 6, Issue 3 And 4 (Autumn & Winter 2004)
Advances in Cognitive Sciences 2004, 6(3 And 4): 28-36 |
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Abstract: (2478 Views)
Objective: This study aimed to evaluate the effect of parazosin (alpha-l adrenergic receptor antagonist), yohimbine (alpha-2 adrenergic receptor antagonist), bicuculline (GABAA receptor antagonist), CGP35348 (GABAB receptor antagonist), and lidocaine (calcium channel blocker) on the analgesic effect of carbamazepine on white NMRI-mice, in the both phases of the formalin test.
Method: In this interventional experiment, the analgesic effects of carbamzepine, prazosin, yohimbine, bicuculline, CGP35348, and lidocaine were tested by performing an intraperitoneal injections during the formalin test. Also the effect of the mentioned drugs on the analgesic effect of carbamazepine was assessed. The formalin test was used as a model of chronic pain, in which formalin 0.5% was infused into the plantar surface of the mouse foot as the painful stimulus animal's response was observed. Data at minutes 0-5 were considered as measures of acute pain, data at minutes 5-16 were considered as the chronic pain.
Results: Different doses of intraperitoneal injections of carbamazepine (3, 5,7, 15,30 mg/kg), lidocaine (5, 10,20 mg/kg), prazosin (0.125, 0.25, 0.5 mg/kg), yohembine (0.25, 0.5 mg/kg), bicuculline (1, 3, 5 mg/kg), and CGP35348 (100, 200 mg/kg) showed analgesic effects in the both phases of the formalin test. The analgesic effect of carbamazepine was not influenced by injection of other medications except lidocaine. Simultaneous administration of lidocaine augmented the analgesic effect of carbamazepine in the first phase of the formalin test but not the second. It should be mentioned that the administration of bicuculline (0.75 mg/kg) was associated with induction of hyperalgesia in the second phase, probably by blocking a group of GABA receptors and thus inducing pain.
Conclusion: With regard to the effect of lidocaine on carbamazepine in the acute phase it is suggested that at least a part of the analgesic effect of the carbamazepine is related to a sodium channel mechanisms.
Method: In this interventional experiment, the analgesic effects of carbamzepine, prazosin, yohimbine, bicuculline, CGP35348, and lidocaine were tested by performing an intraperitoneal injections during the formalin test. Also the effect of the mentioned drugs on the analgesic effect of carbamazepine was assessed. The formalin test was used as a model of chronic pain, in which formalin 0.5% was infused into the plantar surface of the mouse foot as the painful stimulus animal's response was observed. Data at minutes 0-5 were considered as measures of acute pain, data at minutes 5-16 were considered as the chronic pain.
Results: Different doses of intraperitoneal injections of carbamazepine (3, 5,7, 15,30 mg/kg), lidocaine (5, 10,20 mg/kg), prazosin (0.125, 0.25, 0.5 mg/kg), yohembine (0.25, 0.5 mg/kg), bicuculline (1, 3, 5 mg/kg), and CGP35348 (100, 200 mg/kg) showed analgesic effects in the both phases of the formalin test. The analgesic effect of carbamazepine was not influenced by injection of other medications except lidocaine. Simultaneous administration of lidocaine augmented the analgesic effect of carbamazepine in the first phase of the formalin test but not the second. It should be mentioned that the administration of bicuculline (0.75 mg/kg) was associated with induction of hyperalgesia in the second phase, probably by blocking a group of GABA receptors and thus inducing pain.
Conclusion: With regard to the effect of lidocaine on carbamazepine in the acute phase it is suggested that at least a part of the analgesic effect of the carbamazepine is related to a sodium channel mechanisms.
Type of Study: Research |
Subject:
Special
Received: 2004/05/9 | Accepted: 2004/07/17 | Published: 2004/09/22
Received: 2004/05/9 | Accepted: 2004/07/17 | Published: 2004/09/22
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