ATP-sensitive potassium channels mediate norepinephrine- and morphine-induced antinociception at the spinal cord level.
The effects of intrathecally (i.t.) administered glibenclamide, a blocker of adenosine triphosphate-sensitive potassium ( KATP) channels, on antinociception produced by i.t. norepinephrine, morphine, or 5'-N-ethylcarboxamide adenosine, an adenosine agonist, were investigated using tail-flick assay. The results showed that: 1) i.t. norepinephrine (1 nmol), morphine (0.5 nmol) and 5'-N-ethylcarboxamide adenosine (0.5 nmol) elicited prolongation of tail-flick latency, 2) i.t. glibenclamide given in 2 different doses (5 and 10 nmol) exhibited no effects on tail-flick latency, 3) the antinociception produced by norepinephrine (1 nmol) and morphine (0.5 nmol) was blocked by glibenclamide in a dose-dependent manner, 4) glibenclamide failed to modulate the effects of 5'-N-ethylcarboxamide adenosine on tail-flick latency. These observations suggest that KATP channels may play an important role in norepinephrine- and/or morphine-induced antinociception at the spinal level.
Yang
S W
SW
Department of Neurobiology, Shanxi Medical College, Taiyuan, PR China.
Kang
Y M
YM
Guo
Y Q
YQ
Qiao
J T
JT
Dafny
N
N
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D019830:Adenosine-5'-(N-ethylcarboxamide) / Q000494:pharmacology; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D005260:Female; D005905:Glyburide / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology*; D010147:Pain Measurement / Q000187:drug effects*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects; D013116:Spinal Cord / Q000187:drug effects*
D000316:Adrenergic alpha-Agonists; D000701:Analgesics, Opioid; D007004:Hypoglycemic Agents; D015221:Potassium Channels; D019830:Adenosine-5'-(N-ethylcarboxamide); D009020:Morphine; D000255:Adenosine Triphosphate; D005905:Glyburide; D009638:Norepinephrine