Sexual dimorphism in endothelin-1 induced mechanical hyperalgesia in the rat

作者：Joseph Elizabeth K; Levine Jon D^*

来源：Experimental Neurology, 2012, 233(1): 505-512.

DOI：10.1016/j.expneurol.2011.11.030

• Endothelin
• Gender
• Hyperalgesia
• Rat
• Sexual dimorphism
• Stimulus
• Enhancement

While the onset of mechanical hyperalgesia induced by endothelin-1 was delayed in female rats, compared to males, the duration was much longer. Given that the repeated test stimulus used to assess nociceptive threshold enhances hyperalgesia, a phenomenon we have referred to as stimulus-induced enhancement of hyperalgesia, we also evaluated for sexual dimorphism in the impact of repeated application of the mechanical test stimulus on endothelin-1 hyperalgesia. In male and female rats, endothelin-1 induced hyperalgesia is already maximal at 30 min. At this time stimulus-induced enhancement of hyperalgesia, which is observed only in male rats, persisted for 3-4 h. In contrast, in females, it develops only after a very long (15 day) delay, and is still present, without attenuation, at 45 days. Ovariectomy eliminated these differences between male and female rats. These findings suggest marked, ovarian-dependent sexual dimorphism in endothelin-1 induced mechanical hyperalgesia and its enhancement by repeated mechanical stimulation.

• 出版日期2012-1