The effect of inducing morphine tolerance on anti-allodynic action of gabapentin in spinal nerve-ligated rat.
10.4097/kjae.2009.56.1.74
- Author:
Jin Hua CUI
1
;
Hyung Gon LEE
;
Woong Mo KIM
;
Hong Beom BAE
;
Myung Ha YOON
;
Jeong Il CHOI
Author Information
1. Department of Anesthesiology and Pain Medicine, Chonnam National University, Medical School, Gwangju, Korea. aneszzz@naver.com
- Publication Type:Original Article
- Keywords:
Antiallodynia;
Gabapentin;
Morphine;
Neuropathic pain;
Tolerance
- MeSH:
Acute Pain;
Amines;
Animals;
Catheters;
Cyclohexanecarboxylic Acids;
gamma-Aminobutyric Acid;
Humans;
Hyperalgesia;
Ligation;
Male;
Morphine;
Neuralgia;
Rats;
Rats, Sprague-Dawley;
Spinal Nerves;
Subarachnoid Space
- From:Korean Journal of Anesthesiology
2009;56(1):74-78
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: Morphine is more effective in inflammatory or acute pain than neuropathic pain. Recently, some reports demonstrated that the development and maintenance of opioid tolerance and neuropathic pain have similar aspects. Here, we evaluated whether morphine tolerance affects the anti-allodynic effect of gabapentin in spinal-nerve ligated rat. METHODS: Male Sprague-Dawley rats weighing 100-120 g received L5,6 spinal nerve ligation to induce neuropathic pain. Rats showing allodynia were implanted with intrathecal (i.t.) catheter to administer the experimental drugs into the subarachnoid space. To induce olerance to morphine, 15 microgram of morphine was injected via i.t. catheter twice a day for 7 days, and the effect of i.t. gabapentin on the paw withdrawal threshold was examined using the von Frey test before and after the development of morphine tolerance. RESULTS: Ligation of spinal nerves decreased the paw withdrawal threshold. Intrathecal morphine initially increased the paw withdrawal threshold, but this effect decreased gradually over time. However, morphine tolerance did not influence the effect of gabapentin on withdrawal threshold. CONCLUSIONS: Morphine tolerance did not affect gabapentin efficacay in a neuropathic pain model.
