[Microinjection of opioid antagonist into periaqueductal gray blocks formalin-induced alterations of substance P in spinal dorsal horn].
Using formalin injected into the rat's hind paw as nociceptive stimulation, the effect of naloxone and beta-endorphin (beta-EP) antiserum microinjected into the periaqueductal gray (PAG) on the level of substance P like immunoreactivity (SPLI) of the spinal dorsal horn was observed. After formalin injection, a significant increase in SPLI was found as compared with the control (P < 0.01). After naloxone or beta-EP antiserum microinjection, SPLI level in the dorsal horn was decreased (P < 0.05). It is thus suggested that nociceptive stimulation induce the release of beta-EP in the PAG, which, in turn, modulate SP release in the spinal dorsal horn.
Du
J H
JH
Department of Neurobiology, Shanghai Medical University.
He
L F
LF
D000818:Animals; D007106:Immune Sera; D008297:Male; D008845:Microinjections; D009270:Naloxone / Q000494:pharmacology*; D009619:Nociceptors / Q000187:drug effects*; D010446:Peptide Fragments / Q000494:pharmacology*; D010487:Periaqueductal Gray / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013116:Spinal Cord / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism*; D001615:beta-Endorphin / Q000494:pharmacology*
D007106:Immune Sera; D010446:Peptide Fragments; D013373:Substance P; D009270:Naloxone; D001615:beta-Endorphin