A "receptor" for protons in small neurons of trigeminal ganglia: possible role in nociception.

Neurons of the rat's trigeminal ganglion were enzymatically isolated and investigated under the conditions of intracellular perfusion and voltage clamp. Recently discovered proton-activated sodium conductance was found in about half of the neurons. The majority of these proton-sensitive neurons (74%) were less than 26 micrometer in diameter, whereas most of the proton-insensitive cells (75%) were larger than 26 micrometer in diameter. The possibility is discussed that the small proton-sensitive neurons may participate in nociception.