Mechanisms involved in facial heat hyperalgesia induced by endothelin-1 in female rats.

Objective: Pronociceptive responses to endothelins in the trigeminal system seem to be mediated by ET and ET receptors, which have been shown to be expressed in neurons of the trigeminal ganglion of humans and rats. The present study aimed to evaluate the ability of endothelin-1 (ET-1) to induce facial heat hyperalgesia in female rats, the contribution of ET and ET receptors to this response, as well as the mechanisms underlying heat hyperalgesia induced by ET-1.

Design: ET-1 (100pmol/50μL) was injected into the upper lip and heat hyperalgesia was evaluated for up to 6h.