Manzumeh- Shamsi Meimandi
Neuroscience Research Center, Kerman University of Medical Sciences, Iran
Gholam Reza- Sepehri
Department of Physiology and Pharmacology, Faculty of Medicine,
Kerman University of Medical Sciences, Iran
Arian Esmaili
Department of Physiology and Pharmacology, Faculty of Medicine,
Kerman University of Medical Sciences, Iran
ABSTRACT
In this study gonadectomy was undertaken to evaluate gender-differences in antinociceptive effects of morphine. Ninety NMRI adult male and female rats in three groups of intact, sham-operated and gonadectomized were tested by Hot-plate assay. The latency time was recorded three times before and every 15 min until 2 h after morphine (7 and 12 mg kg -1 s.c.). Same procedure was repeated in days 7, 21 and 35 after surgical operation. The data were expressed as latency time and maximum possible effect (%MPE).There was not any significant gender differences in base line latency time in intact and also in sham operated rats at days 7, 21 and 35, while in gonadectomized rats the base line latency time of male were decreased significantly at 21st and 35th day compared to female rats. The analgesic response to 12 mg kg -1 s.c. of morphine was significantly higher in intact male rats while in day 35th after gonadectomy it was decreased significantly compared to females. By 7 mg kg -1 s.c. of morphine %MPE of males was decreased only in 35th day. In sham operated and all other groups no gender differences was observed in %MPE. So gonadectomy decreased pain threshold sensation especially in male rats. The analgesic response to morphine decreased in both sexes but in male rats it was more pronounced, especially by higher doses of morphine (12 mg kg -1 s.c.). This phenomenon may be described by different density and affinity of opioid receptors which their function depends on morphine dosage and/or sex hormone level.
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How to cite this article
Manzumeh- Shamsi Meimandi, Gholam Reza- Sepehri and Arian Esmaili, 2005. Gender Related Differences in Antinociceptive Properties of Morphine after
Gonadectomy in Male and Female Rats. International Journal of Pharmacology, 1: 167-171.
DOI: 10.3923/ijp.2005.167.171
URL: https://scialert.net/abstract/?doi=ijp.2005.167.171
DOI: 10.3923/ijp.2005.167.171
URL: https://scialert.net/abstract/?doi=ijp.2005.167.171
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