Bicuculline and spinal inhibition produced by dorsal column stimulation in the cat.
In barbiturate anaesthetized cats, dorsal column stimulation inhibited ascending volleys recorded in the antero-lateral spinal fasciculus from electrical stimulation of the contralateral tibial nerve and the excitation of neurones of the dorsal horn by noxious heating of the skin. The inhibition was non-selective. Intravenous bicuculline (0.2-0.6 mg/kg) reduced dorsal column induced inhibition of ascending volleys. Bicuculline but not strychnine, administered electrophoretically from micropipettes, reduced dorsal column induced inhibition of the excitation of dorsal horn neurones by noxious heat. These findings suggest that the inhibition studied was produced by release of gamma-aminobutyric acid. This amino acid may play a role in the clinical suppression of pain produced by dorsal column stimulation.
Duggan
A W
AW
Department of Pharmacology, John Curtin School of Medical Research, Australian National University, P.O. Box 334, Canberra City, A.C.T. 2601 Australia.
Foong
F W
FW
D000344:Afferent Pathways / Q000187:drug effects; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology*; D002415:Cats; D004558:Electric Stimulation; D005727:Ganglia, Spinal / Q000187:drug effects*; D005998:Glycine / Q000378:metabolism; D006614:Hindlimb / Q000294:innervation; D008465:Mechanoreceptors / Q000187:drug effects; D009413:Nerve Fibers, Myelinated / Q000187:drug effects; D009433:Neural Inhibition / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects; D009619:Nociceptors / Q000187:drug effects; D012867:Skin / Q000294:innervation; D013116:Spinal Cord / Q000187:drug effects*; D013331:Strychnine / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects; D013979:Tibial Nerve / Q000187:drug effects; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D005680:gamma-Aminobutyric Acid; D013331:Strychnine; D005998:Glycine; D001640:Bicuculline