Action of capsaicin on dorsal root-evoked synaptic transmission to substantia gelatinosa neurons in adult rat spinal cord slices.
An action of capsaicin was investigated on dorsal root-evoked synaptic transmission to substantia gelatinosa (SG) neurons in adult rat spinal cord slices by use of the whole-cell voltage-clamp technique. In 79% of neurons examined, superfusing capsaicin (1 microM) for 30 s depressed a C-fiber-evoked excitatory synaptic current in a manner sensitive to a capsaicin-receptor antagonist, capsazepine (10 microM). On the contrary, Adelta-fiber-evoked excitatory and inhibitory synaptic currents were unaffected by capsaicin in all of cells tested. It is concluded that capsaicin specifically acts on C-afferents, resulting in an inhibition of evoked excitatory transmission to the SG; this may contribute to, at least in part, an acute analgesic action of capsaicin.
Yang
K
K
Department of Physiology, Saga Medical School, 5-1-1 Nabeshima, Saga 849-8501, Japan.
Kumamoto
E
E
Furue
H
H
Li
Y Q
YQ
Yoshimura
M
M
D000818:Animals; D002211:Capsaicin / Q000031:analogs & derivatives / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects; D005727:Ganglia, Spinal / Q000187:drug effects*; D066298:In Vitro Techniques; D009474:Neurons / Q000187:drug effects*; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects*; D013376:Substantia Gelatinosa / Q000166:cytology / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*
C071423:capsazepine; D002211:Capsaicin