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. 1974 Apr;238(1):1–15. doi: 10.1113/jphysiol.1974.sp010507

Changes of of extracellular potassium concentration induced by neuronal activity in the spinal cord of the cat

N Kříž, Eva Syková, E Ujec, L Vyklický
PMCID: PMC1330859  PMID: 4838796

Abstract

1. Changes of extracellular K+ concentration, [K]e, arising in the spinal cord of the cat in response to an afferent stimulation were studied by means of K+-specific micro-electrodes.

2. In the most active areas of the spinal cord a single volley in a large afferent input like the common peroneal nerve or the posterior tibial nerve produced a transient increase in [K]e of 0·05-0·1 mM, which reached its peak in 0·2-0·3 sec and it declined in about 3 sec.

3. Much higher increases in [K]e were found during repetitive stimulation of an afferent input. The highest increase (by 3 mM) was at 100 Hz, but even at 1 Hz a significant increase of 0·25 mM was observed. Equilibration of accumulated K+ was slow with a time constant of about 6 sec, which is much longer than could be expected for the same process in free solution.

4. A characteristic distribution of increased [K]e was found in the spinal cord in response to 100 Hz afferent stimulation. The highest increase of 3 mM was found in and around the intermediate nucleus, but at depths between 0·9-1·8 mm the [K]e increase exceeded 1 mM.

5. In the ventral horns afferent stimulation (100 Hz) increased [K]e by 0·25 mM, while the same stimulation of the ventral root resulted in a [K]e increase of less than 0·05 mM.

6. The consequences of Ke+ accumulation after neuronal discharge are discussed in respect to its possible role in the depolarization of primary afferent terminals.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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