Subconvulsive doses of intracisternal bicuculline methiodide, a GABAA receptor antagonist, produce potent analgesia as measured in the tail pinch test in mice.
Bicuculline methiodide, a GABAA antagonist produced potent analgesia in the tail pinch test when it was given intracisternally (i.c.) but not intrathecally (i.t.). The ED50 was 5 ng/mouse. This analgesia was antagonized by i.c. muscimol, a GABAA agonist. On the contrary, muscimol (i.t.) produced bicuculline-reversible analgesia. These findings suggest that brain GABA may transmit the nociceptive information while GABA in the spinal cord may inhibit it.
D000700:Analgesics; D000818:Animals; D001640:Bicuculline / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D051379:Mice; D009118:Muscimol / Q000494:pharmacology; D011930:Reaction Time / Q000187:drug effects; D011963:Receptors, GABA-A / Q000187:drug effects*
D000700:Analgesics; D011963:Receptors, GABA-A; D009118:Muscimol; C017069:bicuculline methiodide; D001640:Bicuculline