TY - JOUR
T1 - Characterization of voltage-gated potassium currents in dorsal root ganglion neurons of neonatal rats
AU - Kim, J.
AU - Sung Jun Jung, Jun Jung
AU - Sang Jeong Kim, Jeong Kim
AU - Kim, J.
PY - 1997/12/1
Y1 - 1997/12/1
N2 - Dorsal root ganglion (DRG) is composed of neuronal cell bodies of primary afferents with diverse functions. Various types of ion channels present on DRG neurons may reflect those functions. In the present study, voltage-gated potassium currents in DRG neurons of neonatal rats were characterized by whole-cell voltage clamp method. Two types of delayed rectifier and three types of transient potassium currents were identified according to their electrophysiological properties. The delayed rectifier currents were named I(Ke) (early inactivating) and I(Kl) (late inactivating). Steady state inactivation of I(Ke) began from -100 mV lasting until -20 mV. I(Kl) could be distinguished from I(Ke) by its inactivation voltage range, from -70 mV to +10 mV. Three transient currents were named I(Af) (fast inactivation), I(Ai) (intermediate inactivation kinetics), and I(As) (slow inactivation). I(Af) showed fast inactivation with time constant of 10.6±2.0 msec, I(Ai) of 36.9±13.9 msec, and I(As) of 60.6±2.9 msec at +30 mV, respectively. They also had distinct steady state inactivation range of each. Each cell expressed diverse combination of potassium currents. The cells most frequently observed were those which expressed both I(Kl) and I(Af), and they had large diameters. The cells expressing I(Ke) and expressing I(Ke), I(Ai), and I(As) usually had small diameters. Judging from cell diameter, capsaicin sensitivity or action potential duration, candidates for nociceptor were the cells expressing I(Ke), expressing I(Ke) and I(Ai), and expressing I(Ke) and I(As). The types and distribution of potassium currents in neonatal rat DRG were similar to those of adult rat DRG (Gold et al, 1996b).
AB - Dorsal root ganglion (DRG) is composed of neuronal cell bodies of primary afferents with diverse functions. Various types of ion channels present on DRG neurons may reflect those functions. In the present study, voltage-gated potassium currents in DRG neurons of neonatal rats were characterized by whole-cell voltage clamp method. Two types of delayed rectifier and three types of transient potassium currents were identified according to their electrophysiological properties. The delayed rectifier currents were named I(Ke) (early inactivating) and I(Kl) (late inactivating). Steady state inactivation of I(Ke) began from -100 mV lasting until -20 mV. I(Kl) could be distinguished from I(Ke) by its inactivation voltage range, from -70 mV to +10 mV. Three transient currents were named I(Af) (fast inactivation), I(Ai) (intermediate inactivation kinetics), and I(As) (slow inactivation). I(Af) showed fast inactivation with time constant of 10.6±2.0 msec, I(Ai) of 36.9±13.9 msec, and I(As) of 60.6±2.9 msec at +30 mV, respectively. They also had distinct steady state inactivation range of each. Each cell expressed diverse combination of potassium currents. The cells most frequently observed were those which expressed both I(Kl) and I(Af), and they had large diameters. The cells expressing I(Ke) and expressing I(Ke), I(Ai), and I(As) usually had small diameters. Judging from cell diameter, capsaicin sensitivity or action potential duration, candidates for nociceptor were the cells expressing I(Ke), expressing I(Ke) and I(Ai), and expressing I(Ke) and I(As). The types and distribution of potassium currents in neonatal rat DRG were similar to those of adult rat DRG (Gold et al, 1996b).
KW - Characterization
KW - Dorsal root ganglion
KW - Neonatal rat
KW - Potassium current
KW - Voltage clamp
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M3 - Article
AN - SCOPUS:0031426361
SN - 1226-4512
VL - 1
SP - 613
EP - 624
JO - Korean Journal of Physiology and Pharmacology
JF - Korean Journal of Physiology and Pharmacology
IS - 6
ER -