Microinjection of morphine into nucleus reticularis paragigantocellularis of the rat: suppression of noxious-evoked activity of nucleus raphe magnus neurons.
Microinjection of 1 microgram of morphine into nucleus reticularis paragigantocellularis (Pgc) of anesthetized rats depressed both noxious-evoked and spontaneous activity of nociresponsive neurons in the nucleus raphe magnus (NRM). This effect was naloxone-reversible, and was not observed after control injections dorsal to Pgc. The percent change in spontaneous firing was significantly greater than the percent change in pinch-evoked firing. This reduction in NRM neuronal discharge may contribute to the antinociceptive effects produced by microinjection of morphine into Pgc.
D000818:Animals; D001931:Brain Mapping; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects*; D008845:Microinjections; D009020:Morphine / Q000494:pharmacology* / Q000627:therapeutic use; D009434:Neural Pathways / Q000187:drug effects; D010146:Pain / Q000188:drug therapy* / Q000503:physiopathology; D011903:Raphe Nuclei / Q000503:physiopathology*; D051381:Rats; D011919:Rats, Inbred Strains
D009020:Morphine