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Updated: Aug 12, 2026
Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
Sex differences in thermoregulation after acute and chronic morphine administration in mice
1Department of Psychology and Center for Developmental Neuroscience, The College of Staten Island, City University of New York, NY 10314, Staten Island, USA. kest@postbox.csi.cuny.edu
Abstract:
Sex differences in thermoregulation have been reported following acute morphine administration in rats only. This study assessed whether male and female mice also differ in thermoregulatory responses following acute and chronic morphine administration. Females displayed significantly higher baseline colorectal temperature and greater morphine (24mg/kg, s.c.) hypothermia (2. 5-fold) on day 1. Two additional days of morphine treatment did not alter baseline temperature readings on Day 4 in either sex, but significantly reduced the morphine hypothermia relative to Day 1 in a sex-dependent manner. Whereas the morphine hypothermia was completely abolished in males, significant hypothermia was still observed in females. Acute and chronic saline injections had no effect on colorectal temperature. The data demonstrate sex differences in the thermoregulatory responses to acute and chronic morphine administration in mice.
