Microinjection of morphine into nucleus reticularis paragigantocellularis of the rat suppresses spontaneous activity of nucleus raphe magnus neurons.
Microinjection of morphine into nucleus reticularis paragigantocellularis of anesthetized rats had differential effects on spontaneous firing of neurons in nucleus raphe magnus (NRM) depending upon the dose of morphine administered. Microinjection of 1 microgram of morphine, a dose which has reliable antinociceptive effects in awake animals, had predominantly suppressive effects on NRM spontaneous firing. Microinjection of 0.35 micrograms of morphine, a dose which has small and unreliable antinociceptive effects in awake animals, had little effect on the activity of NRM cells.
D000818:Animals; D001931:Brain Mapping; D001933:Brain Stem / Q000502:physiology*; D003864:Depression, Chemical; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects* / Q000503:physiopathology; D009020:Morphine / Q000494:pharmacology*; D009434:Neural Pathways / Q000502:physiology; D010146:Pain / Q000503:physiopathology*; D011903:Raphe Nuclei / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D009020:Morphine