Inhibition of gamma-aminobutyric acid receptor-gated chloride currents by noradrenaline in rat spiral ganglion neuron.
- Author:
Ding-Jun ZHA
1
;
Tao XUE
;
Li QIAO
;
Lian-Jun LU
;
Ying LIN
;
Zhi-Ming WANG
;
Yun-Qing LI
;
Jian-Hua QIU
Author Information
- Publication Type:Journal Article
- MeSH: Animals; Chloride Channels; drug effects; GABA-A Receptor Antagonists; pharmacology; Neurons; drug effects; metabolism; Norepinephrine; pharmacology; Patch-Clamp Techniques; Rats; Rats, Sprague-Dawley; Receptors, GABA; metabolism; Spiral Ganglion; drug effects
- From: Chinese Journal of Otorhinolaryngology Head and Neck Surgery 2008;43(4):302-305
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVETo investigate the pharmacological modulatory properties of noradrenaline in the rat spiral ganglion neuron.
METHODSNystatin perforated patch recording technique under voltage-clamp conditions was used to record the modulatory effect of noradrenaline on the current evoked by gamma-amino butyric acid (GABA) in the spiral ganglion neuron.
RESULTSThe reversal potential of the GABA response was about (- 0.78 +/- 0.05) mV (n = 8), which was almost identical to the theoretical Cl- equilibrium potential. At the holding potential of -50 mV, GABA evoked inward current (I(GABA)) over the concentration range of 0.3 to 1 micromol/L. The EC50 and Hill coefficient for GABA were (5.2 +/- 0.5) micromol/L and 1.03 (n = 26). The I(GABA) was suppressed by bicuculline, the selective GABA-A receptor antagonist, and the chloride currents evoked by GABA was inhibited by noradrenaline.
CONCLUSIONSThe result indicates that noradrenaline depressed GABA-A receptor-gated chloride currents, which may contribute to the modulatory effect of sympathetic system on auditory transmission.
