The whole-cell current�Cvoltage (I�CV) curves for individual neurons were generated by calculating the peak outward current at each testing potential and normalizing to the cell capacitance. The conductance�Cvoltage (G�CV) curves were described with the Boltzmann equation: G/Gmax?=?1/[1?+?exp(V0.5???Vm/k)], where V0.5 is the membrane potential at which 50% activation is observed, k is the slope of the function, and Vm is the membrane potential. Differences between the means were tested for significance using paired or unpaired Student��s t-tests, repeated-measures anova followed by Dunnett��s post hoc test, or two-way anova followed by Bonferroni��s post hoc test. A p-value of <?0.05 was considered to be statistically significant. Three weeks after <a href="http://en.wikipedia.org/wiki/MAP2K7
">MAP2K7 diabetic induction, the diabetic rats showed a large reduction in their paw withdrawal thresholds in response to the pressure stimulus applied to the hindpaw (Chen and Pan 2002; Chen et?al. 2009), as compared with age-matched DNA Damage inhibitor
control rats (control rats: 121.11?��?3.51?g; diabetic rats: 77.78?��?3.64?g, p?<?0.05, t-test). The DRG neurons were divided into three groups according to their cell diameters, which were measured with a calibrated eyepiece reticule: small (<?30?��m), medium (30�C40?��m), and large (>?40?��m). To determine the whole-cell Kv currents in these three groups of DRG neurons, we normalized the peak outward current to the cell capacitance. There were no significant differences in the capacitance of the three groups of DRG neurons between the diabetic rats (small, 26.23?��?1.08?pF, n?=?39; medium, 62.98?��?3.75?pF, n?=?24; large, 114.51?��?6.35?pF, n?=?17) and age-matched control rats (small, 25.77?�� 1.99?pF, n?=?41; medium, 60.33?��?2.42?pF, n?=?22; large, 121.94?��?7.36?pF, n?=?19; p?<?0.05, two-way anova). The total Kv current density was significantly reduced in diabetic rats in both medium and large DRG neurons, as compared with the total Kv current density in the DRG neurons from the control group (Figs?1 and 2). The peak current density of both the IA and Ik in the medium and large DRG neurons was also significantly <a href="http://www.selleckchem.com/screening/stem-cell-compound-library.html
">selleck chemicals smaller in the diabetic than in the control group (Figs?1 and 2). Steady-state activation is an important property of Kv currents and can influence the excitability of DRG neurons. Thus, we determined the steady-state activation of total Kv, IA, and Ik in medium and large DRG neurons. There was a significant depolarizing shift in the total Kv and Ik currents in medium DRG neurons from diabetic rats (total Kv, V0.5?=?10.57?��?1.71?mV; Ik, V0.5?=?13.92?��?3.20?mV), as compared with those from the control rats (total Kv, V0.5?=?2.77?��?2.11?mV; Ik, V0.5?=?4.85?��?2.43?mV; t-test) (Fig.?1d).