J Korean Neurol Assoc.  2007 May;25(2):199-205.

Effects of S-nitroso-N-acetylpenicillamine on the Neuronal Excitability of the Medial Vestibular Nuclear Neuron

• Kim HW
• Cho KH
• Jang S
• Jeong HS
• Park JS

Abstract

BACKGROUND: The medial vestibular nucleus is the largest one among the vestibular nuclei and known to play important roles not only in normal vestibular information processing but also in vestibular compensation. Glutamate is known to have a key role in vestibular compensation via long term potentiation and depression. But the action of nitric oxide related with glutamate is poorly studied. This experiment was designed to explore the effects of nitric oxide on the neuronal activity of a rat medial vestibular nuclear neuron using a nitric oxide enhancing drug, S-nitroso-N-acetylpenicillamine (SNAP).
METHODS
Experiments were carried out on Sprague-Dawley rats aged 14 to 17 days. Neurons of MVN were obtained via enzymatic dissociation of a microtomized rat brainstem. Whole-cell membrane potentials were recorded at room temperature by using standard patch-clamp techniques. Action potentials were obtained after administration of SNAP. Changes of potassium currents were recorded using SNAP and ODQ (1H-[1, 2, 4] oxadiazolo [4, 3-a] quinozalin-1-one), an inhibitor of guanylyl cyclase.
RESULTS
The mean spike frequency of action potentials was increased by adding SNAP. The mean amplitude of afterhyperpolarization was decreased by adding SNAP. The mean potassium current of medial vestibular nuclear neurons was decreased by SNAP. ODQ inhibited the SNAP-induced potassium currents.
CONCLUSIONS
These results suggest that nitric oxide increases the neuronal activity of rat medial vestibular nuclear neurons by inhibiting potassium currents via a cGMP dependent mechanism.

Keyword

S-nitroso-N-acetylpenicillamine; Nitric oxide; Medial vestibular nucleus; Action potential

MeSH Terms

Action Potentials
Animals
Automatic Data Processing
Brain Stem
Compensation and Redress
Depression
Glutamic Acid
Guanylate Cyclase
Long-Term Potentiation
Membrane Potentials
Neurons*
Nitric Oxide
Patch-Clamp Techniques
Potassium
Rats
Rats, Sprague-Dawley
S-Nitroso-N-Acetylpenicillamine*
Vestibular Nuclei
Glutamic Acid
Guanylate Cyclase
Nitric Oxide
Potassium
S-Nitroso-N-Acetylpenicillamine