Journal article
NMDA antagonist modulation of morphine antinociception in female vs. male rats
Pharmacology, biochemistry and behavior, Vol.80(4), pp.639-649
04/2005
Handle:
https://hdl.handle.net/2376/108962
PMID: 15820534
Abstract
NMDA antagonists may be useful for their potential to increase or prolong opioid analgesia while attenuating the development of opioid tolerance and dependence. The purpose of this study was to determine whether there are sex differences in NMDA antagonist modulation of morphine antinociception. Adult female and male Sprague-Dawley rats were injected s.c. with saline or one dose of MK-801 (0.005, 0.01, 0.02, or 0.04 mg/kg), dextromethorphan (5, 10, or 20 mg/kg), or LY235959 (0.5, 1.0, or 2.0 mg/kg) in combination with saline or one dose of morphine (1.8, 3.2, or 5.6 mg/kg), and tested on the 50 degrees C hotplate and tail withdrawal assays 15-120 min post-injection. At the doses examined, only LY235959 produced any antinociception when administered alone. MK-801 attenuated morphine antinociception on both assays, but only at sporadic (inconsistent) dose-combinations. Dextromethorphan increased morphine antinociception on the hotplate but not tail withdrawal assay, at all three morphine doses in males, but only the higher morphine doses in females. In contrast, LY235959 modulated morphine antinociception on both assays; the lowest dose attenuated, and higher doses enhanced morphine antinociception, but the particular morphine doses and assay in which these effects occurred depended on the sex of the subject. Thus, all three NMDA antagonists modulated morphine antinociception in female and male rats, but the direction of this modulation depended on the particular antagonist examined, the nociceptive test, the dose of antagonist and of morphine, and time post-injection.
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Details
- Title
- NMDA antagonist modulation of morphine antinociception in female vs. male rats
- Creators
- Rebecca M Craft - Department of Psychology, Washington State University, Box 644820, Pullman, WA 99164-4820, USA. craft@wsu.eduDarla A Lee
- Publication Details
- Pharmacology, biochemistry and behavior, Vol.80(4), pp.639-649
- Academic Unit
- Psychology, Department of
- Publisher
- United States
- Identifiers
- 99900547247601842
- Language
- English
- Resource Type
- Journal article