The influence of GABA-ergic system on clonidine analgesia in rats.
The effect of agonists and antagonists of GABA-ergic system on analgesia induced by clonidine was investigated in the rat. The compounds activating (muscimol, 1 mg/kg and aminooxyacetic acid; AOAA, 25 mg/kg) or inhibiting GABA-ergic receptors (bicuculline and picrotoxin, in subconvulsive doses 0.5-1 mg/kg) do not change clonidine-induced analgesia. Only the higher dose (2 mg/kg) of muscimol, bicuculline or picrotoxin affected clonidine-induced analgesia. Baclofen, contrary to other GABA agonists, markedly potentiated clonidine-induced analgesia in the dose dependent manner. These results suggest that compounds activating and inhibiting GABA A receptors (muscimol, AOAA, bicuculline and picrotoxin) have a weak influence on clonidine induced analgesia as compared to the effect of baclofen (agonist of GABA B receptors).
Przesmycki
K
K
Department of Anaesthesiology and Intensive Therapy, Medical Academy, Lublin, Poland.
Dzieciuch
J
J
Kleinrok
Z
Z
D000625:Aminooxyacetic Acid / Q000008:administration & dosage / Q000494:pharmacology; D000698:Analgesia; D000704:Analysis of Variance; D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D001640:Bicuculline / Q000008:administration & dosage / Q000494:pharmacology; D003000:Clonidine / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D018755:GABA Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D018756:GABA Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D007279:Injections, Subcutaneous; D008297:Male; D009118:Muscimol / Q000008:administration & dosage / Q000494:pharmacology; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects; D010852:Picrotoxin / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018079:Receptors, GABA / Q000187:drug effects* / Q000378:metabolism
D000625:Aminooxyacetic Acid; D001418:Baclofen; D001640:Bicuculline; D003000:Clonidine; D018755:GABA Agonists; D018756:GABA Antagonists; D009118:Muscimol; D010852:Picrotoxin; D018079:Receptors, GABA