Local corticosteroid application blocks transmission in normal nociceptive C-fibres.
The effect of a locally applied depot form of a corticosteroid on the electrical properties of nerves was investigated in an experimental model. The segmental transmission in electrically stimulated A-fibres and in C-fibres of the plantar nerve in the anaesthetized rat was utilized. A drop of methylprednisolone acetate or vehicle constituent was placed on the dissected plantar nerve proximal to the stimulating electrodes after recording control responses (A-fibre volley in the sciatic nerve and C-fibre evoked reflex discharge in flexor motoneurons). The corticosteroid was found to suppress the transmission in thin unmyelinated C-fibres but not in myelinated A-beta fibres. The effect was found to be due to the corticosteroid per se. The effect was reversed when the corticosteroid was removed, which suggests a direct membrane action.
Johansson
A
A
Department of Anesthesiology, Malmö General Hospital, Sweden.
Hao
J
J
Sjölund
B
B
D000287:Administration, Topical; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D000077555:Methylprednisolone Acetate; D009412:Nerve Fibers / Q000187:drug effects* / Q000502:physiology; D009413:Nerve Fibers, Myelinated / Q000187:drug effects / Q000502:physiology; D009619:Nociceptors / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology
D000893:Anti-Inflammatory Agents; D000077555:Methylprednisolone Acetate; D008775:Methylprednisolone