Inhibitory Effects of Norepinephrine on the Potassium Current of Rat Medial Vestibular Nuclear Neurons

J Korean Neurol Assoc > Volume 23(3); 2005 > Article

Journal of the Korean Neurological Association 2005;23(3): 363-367.

흰쥐 내측 전정핵 뉴론에서 Norepinephrine의 포타슘 전류 억제 효과

정한성, 장명주 황 매 허해룡 조기현a 김병채a 박종성

전남대학교 의과대학 생리학교실, 신경과학교실a

Inhibitory Effects of Norepinephrine on the Potassium Current of Rat Medial Vestibular Nuclear Neurons

Han-Seong Jeong

Departments of Physiology and Neurologya, Chonnam National University Medical School, Gwangju, Korea

Abstract

Background: This study aimed to explore the effects of norepinephrine on the potassium currents of rat medial vestibular nuclear neurons by using the whole-cell patch clamp technique.
Methods: Sprague-Dawley rats aged 14 to 16 days were anesthetized with ether and decapitated. After enzymatic digestion, the portion of the medial vestibular nucleus neurons were obtained by micropunching. The dissociated neurons were transferred into a recording chamber mounted on an inverted microscope and potassium currents were recorded by standard patch-clamp techniques under voltage-clamp modes.
Results: Norepinephrine inhibited the whole potassium currents of the medial vestibular nuclear neurons. Outward potassium currents were more suppressed in 4 mM 4-aminopyridine and norepinephrine added solutions than 4 mM 4-aminopyridine only, but were not suppressed in 10 mM tetraethylammonium and norepinephrine added solutions compared to 10 mM tetraethylammonium only.
Conclusions: These results suggest that norepinephrine blocks the delayed rectifier potassium channels in medial vestibular nuclear neurons. KeyWords:Norepinephrine, Vestibular Nucleus, Potassium current