Brain research
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Comparative Study
Ion channels associated with the ectopic discharges generated after segmental spinal nerve injury in the rat.
In an attempt to identify important ion channels contributing to the generation of ectopic discharges, the present study examined the effects of ion channel blockers on ectopic discharges of injured sensory neurons after spinal nerve ligation. The main focus of the study was to examine the effect of the sodium channel blocker, tetrodotoxin (TTX), in order to identify important subtype(s) (i.e. TTX-sensitive and TTX-resistant) of sodium channels that are involved in ectopic discharge generation. ⋯ In addition, ectopic discharges were inhibited by TTX perfused to the DRG at a dose much lower (average of 22.1 nM) than that required to block TTX-resistant subtypes of sodium channels. The data suggest that TTX-sensitive sodium channels are likely to be involved in the generation of ectopic discharges. The present study also confirmed the results of previous studies on the additional potential roles of potassium and calcium channels, thus suggesting that multiple ion channels are likely to be involved in the generation of ectopic discharges.