Ascending pain pathway is inhibited in dorsal midbrain by
5-HT (serotonin)
Noradrenaline 1
Substance P
Glutamate
The cell bodies of serotonin containing neurons are localized in the raphe nuclei of midbrain and brainstem. ... Serotonin therefore acts descending pathway to modulate spinal pain signals Ref: guyton and hall textbook of medical physiology 12 edition page number:699,700,701
Nervous system