Substance P releases and augments the morphine-evoked release of adenosine from spinal cord.
The effects of substance P on the morphine-evoked release of adenosine were examined. Substance P alone produced a multiphasic effect on release of adenosine, with release occurring at low nanomolar concentrations and at a micromolar concentration, but not at intermediate concentrations. An inactive dose of substance P augmented the morphine-evoked release of adenosine at a nanomolar concentration of morphine. Release of adenosine by substance P alone (1 nM) or substance P/morphine (100 nM/10 nM) was Ca2(+)-dependent and originated from capsaicin-sensitive nerve terminals.
Cahill
C M
CM
Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada.
White
T D
TD
Sawynok
J
J
D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D018377:Neurotransmitter Agents / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism; D013373:Substance P / Q000378:metabolism* / Q000494:pharmacology
D018377:Neurotransmitter Agents; D013373:Substance P; D009020:Morphine; D000241:Adenosine