Met-enkephalin and morphine but not dynorphin inhibit noxious stimuli-induced release of substance P from rabbit dorsal horn in situ.
The effects of locally applied opioids on the release of immunoreactive Substance P (iSP), induced by mechanical stimuli, from the dorsal horn of the rabbit in situ, were investigated. Morphine and met-enkephalin (met-enk), but not dynorphin A (1-17) (DYN), in a concentration of 10 microM, significantly inhibited the evoked release. These inhibitory effects of morphine and met-enkephalin were antagonized by the local application of naloxone (10 microM) to the dorsal horn. These results suggest that the inhibition of the release of Substance P induced by noxious mechanical stimuli may be mediated by mu and delta, but not by kappa opioid receptors.
N
N
Hirota
Y
Y
Kuraishi
Y
Y
Hino
Y
Y
Sato
M
M
Satoh
H
H
Takagi
D000818:Animals; D000870:Anterior Horn Cells / Q000187:drug effects*; D003655:Decerebrate State; D004399:Dynorphins / Q000494:pharmacology*; D004744:Enkephalin, Methionine / Q000494:pharmacology*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009046:Motor Neurons / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects; D010812:Physical Stimulation; D011817:Rabbits; D013373:Substance P / Q000378:metabolism*
D013373:Substance P; D004744:Enkephalin, Methionine; D004399:Dynorphins; D009020:Morphine