[Electrophysiological characteristics of muscarinic cholinergic receptor in rat medial vestibular nucleus neurons by visual patch clamp technique].
OBJECTIVE
To establish the visual patch clamp whole-cell recording technique and study the properties and functional significance of muscarinic receptor-mediated currents in rat medial vestibular nucleus neurons (MVNn).


METHODS
Brain slices containing the MVN were prepared from fifteen Wistar rats. By combining infrared differential interference contrast (IR-DIC) technique and CCD-Camera system with visual patch clamp whole-cell recording technique, twenty healthy neurons were located and muscarinic receptor-mediated currents in rat MVNn were observed and analyzed.


RESULTS
Visual patch clamp technique can be used to make direct localization and to make sure of active neuron. In MVNn, a comparison of the current-voltage relationships before and during the application of muscarine, which revealed an increase in the slope of the I-V curve and the reversal potential for this response lay at (-88.4 +/- 4.9) mV (x +/- s), indicates that the activation of muscarinic cholinergic receptors leads to a decrease in potassium current. The test in the voltage sensitivity of the muscarine-induced response, which showed that the effect had a linear current-voltage relationship and reversed at (-86.7 +/- 3.5) mV, indicates that the potassium current blocked by muscarine corresponds to the voltage-insensitive leak potassium current.


CONCLUSIONS
Visual patch clamp technique, which was considered better than blind patch clamp technique, can improve the success of sealing process. By the analysis of muscarinic receptor-mediated currents, the data provide support that muscarinic cholinergic mechanisms play a prominent role in the modulation of the excitability of MVNn and also offer a new idea for the efficacy of anticholinergic drugs.
Zhang
Yu
Y
Department of Otorhinolaryngology, Union and Technology, Wuhan 430022, China.
Kong
Wei-jia
WJ
Liu
Bang-hua
BH
Guo
Chang-kai
CK
Sun
Da-wei
DW
Xia
Jiao
J
Zhu
Yun
Y
Zhang
Jian
J
D000818:Animals; D055724:Electrophysiological Phenomena; D009474:Neurons / Q000502:physiology; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000502:physiology*; D014726:Vestibular Nuclei / Q000502:physiology*
D011976:Receptors, Muscarinic