Excitatory effects of 5-hydroxytryptamine on the medial vestibular nuclear neuron via the 5-HT2 receptor.
This study was designed to investigate the mechanisms of action of the 5-HT2 receptor on the spontaneous electrical activity and potassium currents of the rat medial vestibular nuclear neurons using whole-cell patch clamp recordings. The spike width of spontaneous action potential was not affected by 5-alpha-methylhydroxytryptamine. The spike frequency and resting membrane potential was increased by 5-alpha-methylhydroxytryptamine. The amplitude of afterhyperpolarization was decreased by 5-alpha-methylhydroxy-tryptamine. The peak current of the potassium currents of the neuron treated with 5-alpha-methylhydroxytryptamine was decreased. After blockade of calcium-dependent potassium currents, 5-alpha-methylhydroxytryptamine did not inhibit potassium currents. These results suggest 5-alpha-methylhydroxytryptamine increases spontaneous firing of the medial vestibular nuclear neurons by inhibiting calcium dependent potassium currents.
Jeong
Han-Seong
HS
Department of Physiology, Chonnam National University Medical School, Gwaugju, Korea.
Lim
Young Chai
YC
Kim
Tae Sun
TS
Heo
Tag
T
Jung
Seung-Mun
SM
Cho
Yong Bum
YB
Jun
Jae Yeoul
JY
Park
Jong-Seong
JS
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004533:Egtazic Acid / Q000494:pharmacology; D004594:Electrophysiology; D008564:Membrane Potentials / Q000502:physiology; D009474:Neurons / Q000187:drug effects*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000187:drug effects*; D012701:Serotonin / Q000494:pharmacology*; D014726:Vestibular Nuclei / Q000166:cytology* / Q000187:drug effects*
D015221:Potassium Channels; D011985:Receptors, Serotonin; D012701:Serotonin; D004533:Egtazic Acid