Non-opioid analgesia of the neuropeptide, neo-kyotorphin and possible mediation by inhibition of GABA release in the mouse brain.
The novel neuropeptide, neo-kyotorphin, produced a naloxone-resistant analgesia in the tail pinch test when given (IC) to mice. Pretreatments with implantation of a morphine pellet or with phentolamine (10 micrograms IT) or with reserpine (10 mg/kg SC) did not attenuate this analgesia, yet the analgesia was antagonized by GABA mimetics, such as muscimol (0.1 microgram IC), nipecotic acid (100 mg/kg IP). Neo-kyotorphin inhibited the Ca2+-dependent and depolarization-evoked release of 3H-GABA, from crude synaptosomes of the lower brain stem of rats. These findings suggest that inhibition of GABA in the brain may in part be involved in neo-kyotorphin-induced analgesia.
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
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Ueda
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Ge
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Satoh
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Takagi
D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D004343:Drug Implants; D004723:Endorphins / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009020:Morphine / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D000700:Analgesics; D004343:Drug Implants; D004723:Endorphins; C019448:kyotorphin; D005680:gamma-Aminobutyric Acid; D009020:Morphine; C036450:neo-kyotorphin; D010646:Phentolamine