Korean J Physiol Pharmacol.  2006 Jun;10(3):131-135.

Effects of Phenylephrine on the Excitability of Medial Vestibular Nuclear Neurons in Rats

• Jeong HS
• Huh HR
• Jang MJ
• Hong SH
• Jang S
• Park J
• Lee SH
• Kim JH
• Park JS

Abstract

Coeruleo-vestibular pathway which connects locus coeruleus and vestibular nuclei is noradrenergic. This study was designed to elucidate the effects of phenylephrine on the spontaneous activity of acutely isolated medial vestibular nuclear neurons of rat by whole-cell patch-clamp technique. Sprague-Dawley rats, aged 14 to 16 days, were used. After enzymatic digestion, dissociated medial vestibular neurons were transferred to a recording chamber mounted on an inverted microscope, and spontaneous action potentials were recorded by standard patch-clamp techniques. In current-clamp mode, the frequency of spontaneous action potential of medial vestibular nuclear neurons was decreased by phenylephrine (n=15). Phenylephrine increased the amplitude of afterhyperpolarization without changes in the resting membrane potential and spike width. In voltage-clamp mode, the whole potassium currents of the medial vestibular nuclear neurons were increased by phenylephrine (n=12). These experimental results suggest that alpha-receptor mediates the inhibitory effects on the neuronal activity of the medial vestibular nuclear neuron.

Keyword

Medial vestibular nucleus; Phenylephrine; Action potential; Potassium currents

MeSH Terms

Action Potentials
Animals
Digestion
Locus Coeruleus
Membrane Potentials
Neurons*
Patch-Clamp Techniques
Phenylephrine*
Potassium
Rats*
Rats, Sprague-Dawley
Vestibular Nuclei
Phenylephrine
Potassium