| Electrical properties and ATP-sensitive K+ channel density of the rat substantia nigra pars compacta neurons |
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Seong-kyu Han1, Jin-bong Park2, Pan-dong Ryu1 |
1Department of Pharmacology, College of Veterinary Medicine, Seoul National University
2Department of Physiology, College of Medicine, Chungnam National University |
| 랫드 흑질 신경세포의 전기적 특성과 ATP-sensitive K+채널의 전류밀도 |
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한성규1, 박진봉2, 류판동1 |
1서울대학교 수의과대학 약리학교실
2충남대학교 의과대학 생리학교실 |
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| Abstract |
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Substantia nigra is known to highly express glibenclamide binding site, a protein associated to ATP-sensitive $K^{+}$ ($K_{ATP}$) channel in the brain. However, the functional expression of $K_{ATP}$ channels in the area is not yet known. In this work, we attempted to estimate the functional expression of $K_{ATP}$ channels in neurons of the substantia nigra pars compacta (SNC) in young rats using slice patch clamp technique. Membrane properties and whole cell currents attributable to $K_{ATP}$ channel were examined by the current and voltage clamp method, respectively. In SNC, two sub-populations of neurons were identified. Type I (rhythmic) neurons had low frequency rebound action potentials ($4.5{pm}0.25Hz$, n=75) with rhythmic pattern. Type II (phasic) neurons were characterized by faster firing ($22.7{pm}3.16Hz$, n=12). Both time constants and membrane capacitance in rhythmic neurons ($34.0{pm}1.27$ ms, $270.0{pm}11.83$ pF) and phasic neurons ($23.7{pm}4.16$ ms, $184{pm}35.2$ pF) were also significantly different. The current density of $K_{ATP}$ channels was $6.1{pm}1.47$ pA/pF (2.44~15.43 pA/pF, n=8) at rhythmic neurons of young rats. Our data show that in SNC there are two types of neurons with different electrical properties and the density of $K_{ATP}$, channel of rhythmic neuron is about 600 channels per neuron. |
| Key Words:
substantia nigra pars compacta, ATP-sensitive $K^{+}$ channel, slice patch |
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