Description
The effects of gender and gonadal hormones on nociceptive responses to intraplantar carrageenan in the rat were investigated. A plantar analgesic meter was used to measure carrageenan-induced changes in paw withdrawal latency (PWL) values, and von Frey monofilaments were used to assess changes in paw withdrawal threshold (PWT) values in response to tactile-evoked (mechanical) stimuli. The data revealed that PWL values were significantly greater in gonadally-intact females than in gonadally-intact males, and this response was abolished by surgical gonadectomies. Gonadally-intact as well as gonadectomized male and female rats also exhibited significant carrageenan-induced decreases in PWT, but neither sex- nor gonadectomy-related differences were detected in the development of mechanical allodynia. These findings demonstrate that intraplantar carrageenan induces nociceptive behaviors in rats that are differentially affected by sex and gonadal hormones.