Differences between nerve terminal impulses of polymodal nociceptors and cold sensory receptors of the guinea-pig cornea
Article first published online: 5 AUG 2004
The Journal of Physiology
Volume 533, Issue 2, pages 493–501, June 2001
How to Cite
Brock, J. A., Pianova, S. and Belmonte, C. (2001), Differences between nerve terminal impulses of polymodal nociceptors and cold sensory receptors of the guinea-pig cornea. The Journal of Physiology, 533: 493–501. doi: 10.1111/j.1469-7793.2001.0493a.x
- Issue published online: 5 AUG 2004
- Article first published online: 5 AUG 2004
- (Received 25 October 2000; accepted after revision 31 January 2001)
Extracellular recording techniques were used to study nerve terminal impulses (NTIs) recorded from single polymodal nociceptors and cold-sensitive receptors in guinea-pig cornea isolated in vitro.
The amplitude and time course of NTIs recorded from polymodal nociceptors was different from those of cold-sensitive receptors.
Bath application of tetrodotoxin (1 μm) changed the time course of spontaneous NTIs recorded from both polymodal and cold-sensitive receptors.
Bath application of lignocaine (lidocaine; 1–5 mm) abolished all electrical activity.
Local application of lignocaine (2.5 and 20 mm) through the recording electrode changed the time course of the NTIs recorded from polymodal nociceptors but not that of NTIs recorded from cold-sensitive nerve endings.
It is concluded that action potentials propagate actively in the sensory nerve endings of polymodal nociceptors. In contrast, cold-sensitive receptor nerve endings appear to be passively invaded from a point more proximal in the axon where the action potential can fail or be initiated.