Pinchenko V. Influence of the experimentally-induced diabetes and changes of an extracellular рН level on low-voltage activated voltage-operated calcium channels in primary sensory neurons of rats.

This dissertation is devoted to the investigation of influence of the experimentally-induced diabetes and changes of an extracellular рН level on biophysical properies of low-voltage activated calcium channels (LVACC) in primary sensory neurons of rats. The influence of external pH and experimentally-induced diabetes on concentration-dependence and biophysical properties (voltage-dependence, kinetics, activation and inactivation) of LVACC were investigated with "patch-clamp" method in "whole cell" configuration in primary sensory neurons of small and middle somatic size. These neurons possess C- and Adelta-fibers and conduct preferably the nociceptive information. Two types of LVACC with different pH-sensitivity and kinetic properties were found and their alfa subunit composition was suggested. It is shown that small DRG neurons have mainly LVACC with low pH-sensitivity while middle neurons have LVACC with high pH-sensitivity. We found that in DRG neurons of small size STZ-diabetes did not produce anysignificant changes in the density of LVA currents. While in DRG neurons of middle size experimentally induced diabetes produced significant reduction of LVA current density. The obtained results are correlated with our previous data on pH-sensitivity of different LVA subtypes and these data can provide one more alternative hypothesis of the origin and development of diabetic neuropathies.