Anabolic-androgenic steroid effects on pain and opioid analgesia

R. Craft; L. Sternod; R. Wood

doi:10.1016/j.jpain.2007.02.077

It has been suggested that anabolic-androgenic steroids such as testosterone promote body building in part because they reduce pain sensitivity. The present study was designed to determine whether male rats’ nociceptive and opioid antinociceptive sensitivity changed after chronic exposure to high-dose testosterone. Adult, gonadally intact Sprague-Dawley male rats were given once-daily injections of testosterone propionate (TP, 5 mg/kg s.c.) or safflower oil vehicle for 28 days. Beginning 3 hr after the vehicle or TP injection on day 28, latency to respond on two tests of acute thermal nociception (hotplate and tail withdrawal) and a test of acute mechanical nociception (paw pressure) was recorded, or behavior on a test of inflammatory nociception (formalin test) was recorded; in the latter group of rats, the development of thermal hyperalgesia and mechanical allodynia was also evaluated periodically for a month after formalin injection, during which daily vehicle or TP injections were continued. Morphine antinociceptive sensitivity was also determined in each test. Preliminary data indicate that chronic TP-treated males gained significantly less weight, had significantly smaller epididymal fat pads and larger seminal vesicles (per kg body weight) than vehicle-treated controls. Hotplate, tail withdrawal and paw pressure latencies did not differ significantly between TP- and vehicle-treated rats. Morphine antinociceptive sensitivity was similar between TP- and vehicle-treated rats on the tests of acute thermal nociception, whereas a subset (approximately 35%) of TP-treated rats were substantially more sensitive than vehicle-treated rats to morphine on the paw pressure test. TP treatment blocked the development of thermal hyperalgesia but enhanced the development of mechanical allodynia during the month following formalin injection. These data suggest that chronic anabolic-androgenic steroid use does not consistently reduce pain or enhance opioid analgesia.

Anabolic-androgenic steroid effects on pain and opioid analgesia

Related links

Abstract

Metrics

Details