From the Department Of Physiology, Shaheed Beheshti University of Medical Sciences, Tehran, IslamicRepublic of Iran.
Abstract: (4559 Views)
Bulbospinal noradrenergic pathways are shown to have an important role in
descending inhibition of pain sensation. Locus ceruleus (LC), as a rich noradrenergic
nucleus in the brain stem which has projections into the dorsal horn of the spinal cord,
was evaluated for antinociceptive activity by using tonic and phasic pain models in
the rat. LC-lesioned rats demonstrated moderate increase in both phases of the
formalin test, but did not show any effect to thermal noxious stimuli, applied in the
tail-flick test. These results indicate the relative involvement of LC in inhibition of
tonic, but not phasic, pain.