Modulation of leak K(+) channel in hypoglossal motoneurons of rats by serotonin and/or variation of pH value.
- Author:
Xue-Feng XU
1
;
Hao-Jan TSAI
;
Lin LI
;
Yi-Fan CHEN
;
Cheng ZHANG
;
Guang-Fa WANG
Author Information
1. Department of Pulmonary Medicine and Central Laboratory of Peking University First Hospital, Beijing 100034, China.
- Publication Type:Journal Article
- MeSH:
Animals;
Animals, Newborn;
Brain Stem;
cytology;
Hypoglossal Nerve;
cytology;
In Vitro Techniques;
Ion Transport;
Membrane Potentials;
Motor Neurons;
metabolism;
Patch-Clamp Techniques;
Potassium Channels, Tandem Pore Domain;
metabolism;
Rats;
Rats, Sprague-Dawley;
Serotonin;
pharmacology
- From:
Acta Physiologica Sinica
2009;61(4):305-316
- CountryChina
- Language:English
-
Abstract:
The cloned TWIK-related acid-sensitive K(+) channel (TASK-1) is sensitive to the pH changes within physiological pH range (pK~7.4). Recently, the native TASK-1-like channel was suggested to be the main contributor to the background (or leak) K(+) conductance in the motoneurons of the brain stem. Serotonin (5-HT) and variation of pH value in perfused solution could modulate these currents. Here we aimed to examine the properties and modulation of the currents by serotonin or variation of pH value in hypoglossal motoneurons of rats. Transverse slices were prepared from the brainstem of neonatal Sprague-Dawley rats (postnatal days 7-8). Hypoglossal motoneurons were used for the study. The leak K(+) current (TASK-1-like current) and hyperpolarization-activated cationic current (I(h)) were recorded with the whole-cell patch-clamp technique. The results showed that these currents were inhibited by acidified artificial cerebrospinal fluid (ACSF, pH 6.0) and activated by alkalized ACSF (pH 8.5). 5-HT (10 mumol/L) significantly inhibited both leak K(+) current and I(h) with depolarization of membrane potential and the occurrence of oscillation and/or spikes. Bath application of Ketanserine, an antagonist of 5-HT₂ receptor, reversed or reduced the inhibitory effect of acidified solution on leak K(+) current and I(h). The results suggest that 5-HT₂ receptors mediate the effects of acidified media on leak K(+) current and I(h) in hypoglossal motoneurons.
