Involvement of endogenous opioids and ATP-sensitive potassium channels in the mediation of apomorphine-induced antinociception at the spinal level: a study using EMG planimetry of flexor reflex in rats.
The effects of intrathecally (i.t.) administered naloxone or glibenclamide, a blocker of adenosine triphosphate-sensitive potassium (KATP) channels, on the antinociception produced by i.t. apomorphine were observed by an integrated electromyogram measurement of hindlimb flexor reflex in lightly pentobarbital-anesthetized rats. The results showed that i.t. apomorphine produced a significant and dose-dependent antinociception and that the antinociception produced by i.t. apomorphine could be blocked dose dependently by i.t. naloxone or glibenclamide. The results suggest that endogenous opioids and ATP-sensitive potassium channels might be sequentially involved in the mediation of apomorphine-induced antinociception at the spinal level.
Hu
W M
WM
Department of Neurobiology, Shanxi Medical University, Taiyuan, China.
Kang
Y M
YM
Qiao
J T
JT
D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D018491:Dopamine Agonists / Q000494:pharmacology; D004576:Electromyography; D005905:Glyburide / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007278:Injections, Spinal; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009619:Nociceptors / Q000187:drug effects / Q000502:physiology*; D018847:Opioid Peptides / Q000502:physiology*; D015221:Potassium Channels / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex / Q000187:drug effects; D013116:Spinal Cord / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*
D018491:Dopamine Agonists; D007004:Hypoglycemic Agents; D009292:Narcotic Antagonists; D018847:Opioid Peptides; D015221:Potassium Channels; D009270:Naloxone; D000255:Adenosine Triphosphate; D001058:Apomorphine; D005905:Glyburide