to address whether morphine inhibits spinal nociceptive transmission when given into the brainstem , the effects of focal electrical stimulation and monosodium s-glutamate ( glu ) given in the periaqueductal gray ( pag ) , the locus coeruleus/subcoeruleus ( lc/sc ) and/or the nucleus raphe magnus ( nrm ) on spinal unit responses to noxious heating ( 50 degrees c ) of the skin were examined and compared with effects produced by morphine ( mor ) .
C0006121
brainstem
C0023951
locus