Immunohistochemical and electrophysiological evidence for omega-conotoxin-sensitive calcium channels in unmyelinated C-fibres of biopsied human sural nerve.
In vitro electrophysiological measurements of Ca2+ potentials in human sural nerve fascicles revealed that Ca2+ conductances might be present on unmyelinated C-fibres. Furthermore, these Ca2+ potentials were partially blocked by omega-conotoxin, a calcium antagonist for the N-type Ca2+ channels. Therefore, immunohistochemical staining with indirect immunofluorescent omega-conotoxin GVIA was used to localize N-type Ca2+ channels in intact and in enzymatically dissociated human sural nerve fascicles. Densities of toxin binding sites were highly heterogeneous throughout the different nerve fascicles investigated and putative N-type Ca2+ channels were localized in about 20% of the unmyelinated C-fibres. Myelinating Schwann cells as well as enzymatically demyelinated axons displayed no specific binding indicating the absence of N-type Ca2+ channels.
Quasthoff
S
S
Department of Neurology, Technical University of Munich, Germany.
Adelsberger
H
H
Grosskreutz
J
J
Arzberger
T
T
Schröder
J M
JM
D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D009412:Nerve Fibers / Q000502:physiology*; D010455:Peptides / Q000494:pharmacology*; D013497:Sural Nerve / Q000502:physiology*; D020866:omega-Conotoxin GVIA
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D010455:Peptides; D020866:omega-Conotoxin GVIA