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Tetrodotoxin‐resistant impulses in single nociceptor nerve terminals in guinea‐pig cornea
Author(s) -
Brock James A.,
McLachlan Elspeth M.,
Belmonte Carlos
Publication year - 1998
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1998.211bf.x
Subject(s) - tetrodotoxin , nociceptor , stimulation , neuroscience , free nerve ending , receptor , sensory nerve , chemistry , guinea pig , anatomy , medicine , nociception , sensory system , biology
1 Extracellular recording techniques have been used to study nerve impulses in single sensory nerve terminals in guinea‐pig cornea isolated in vitro.2 Nerve impulses occurred spontaneously and were evoked by electrical stimulation of the ciliary nerves. 3 The nerve impulses were identified as originating in polymodal receptors, mechano‐receptors or ‘cold’ receptors. All three types are believed to be nociceptors. 4 Tetrodotoxin (TTX, 1 μ m ) blocked nerve impulses evoked by electrical stimulation of the ciliary nerves. However, ongoing and/or naturally evoked nerve impulses persisted in the presence of TTX in all three types of receptors. Lignocaine (lidocaine; 1 m m ) blocked all electrical activity. 5 TTX‐resistant sodium channels therefore play a major role in generating the action potentials that signal pain to the brain.