Chonnam Med J.  2001 Jun;37(2):99-108.

K+ Currents in Medial Vestibular Nuclear Neurons

• Jeong HS
• Cha MJ
• Kim TS
• Park JS

Abstract

Whole-cell voltage clamp techniques were used to identify and characterize outward K+ currents in acutely isolated medial vestibular nuclear neurons. When cells were held at -70 mV and depolarized from -60 mV to + 40 mV in 10 mV increments, sustained outward currents were evoked. Voltage and time dependent activation and inactivation kinetics were analyzed. The steady-state activation (V1/2 = 18.7 mV, slope factor = -13.5 mV) and inactivation (V1/2 = -48.5, slope factor = +24.3 mV) curves were plotted and these fitted well Boltzmann equation. Replacement of external Ca2+ (2 mM) with Co2+ (2 mM) decreased the amplitude of current. The early transient outward current was reduced by application of 4-aminopyridine (4 mM). The sustained outward current was reduced by application of high dose TEA (10 mM). These results suggest that at least 3 types of K+ currents are exist in the medial vestibular nuclear neurons of the rat: Ca2+-activated K+ current (KCa), type A K+ current (KA), and delayed rectifier K+ current (KV). These ionic currents may play essential roles in regulating membrane excitability in the rat vestibular nuclear neuron.

Keyword

Vestibular nuclear neuron; Ca2+-activated K+current; Type A K+current; Delayed rectifier K+ current

MeSH Terms

4-Aminopyridine
Animals
Kinetics
Membranes
Neurons*
Patch-Clamp Techniques
Rats
Tea
4-Aminopyridine
Tea