Abstract
The present study was undertaken to compare the effects of the α 2-adrenoceptor antagonist yohimbine on inhibition of C-fiber-evoked responses of dorsal horn neurons produced by electrical stimulation of the lateral reticular nucleus (LRN) and the Locus coeruleus (LC) in the rat. In the majority of neurons, C-fiber-evoked responses were significantly inhibited by 53.84±5.02% and 57.63±5.79% of control by LRN and LC stimulation, respectively, whereas in less than half of the neurons, A-fiber-evoked responses were reduced by 20.99±6.06% and 21.78±4.48% of control, respectively. After systemic or spinal administration of yohimbine, LC-induced inhibition of C-fiber-evoked responses was not affected. In contrast, LRN-induced inhibition was markedly attenuated by yohimbine. The results suggest that α 2-adrenoceptors may be involved in mediation of inhibition of spinal nociception induced by stimulation of LRN but not by LC.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have