title: Resonance characteristic and its ionic basis of rat mesencephalic trigeminal neurons.
abstract: Intrinsic resonant frequency properties of neurons in the brain provide a basis for different behavioral states and determine the responding modality (i.e. excitability) of different neurons. Previously, three types of excitability behaviors in rat Mesencephalic V neurons were found. To investigate the different resonant frequency and ionic current mechanisms underlying different resonances among three types of excitability, we performed whole-cell patch recordings and applied ZAP current on Mesencephalic V cells (N=70) in rat slices. The results show that: Class 2 neurons (30/30) have two resonances with U-shaped voltage dependence. One is a high frequency resonance (75.4 ± 2.11 Hz) significant at depolarized potentials (about -50 mV) and the other is a low frequency resonance (5.46 ± 0.31 Hz) significant at hyperpolarized potentials (about -70 mV). Voltage clamp experiments reveal two non-inactivating currents operating in the subthreshold voltage range: (1) 4-aminopyridine sensitive K(+) current, which activates at membrane potentials positive than -60 mV and was blocked by 4-AP (50 µM), was underlying the high frequency resonance of Class 2 neuron; (2) h-current, which activates negative than -60mV and was blocked by the hyperpolarization-activated cyclic nucleotide-gated channel blocker ZD7288 (10 µM), was underlying the low frequency resonance. Class 1 neurons do not show voltage-dependence resonant behaviors (10/10). Class 3 neurons (23/30) have two resonances, which are similar with Class 2 in both resonant frequency and currents. Our results provide clear evidence for the existence of multiple kinds of frequency resonances and how the relationship between the resonant frequency and the ionic current is based in Mesencephalic V neurons.
authors.affiliation: The 323 Military Hospital, 6 West Jian-she Road, Xi׳an 710054, P.R. China. Electronic address: yangjing323@163.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.affiliation: Institute of Neuroscience, The Fourth Military Medical University, 17 Chang-le West Road, Xi׳an 710032, P.R. China.
authors.forename: Sanjue
authors.initials: S
authors.lastname: Hu
authors.affiliation: The 323 Military Hospital, 6 West Jian-she Road, Xi׳an 710054, P.R. China.
authors.forename: Fujun
authors.initials: F
authors.lastname: Li
authors.affiliation: Institute of Neuroscience, The Fourth Military Medical University, 17 Chang-le West Road, Xi׳an 710032, P.R. China. Electronic address: xingjunl@fmmu.edu.cn.
authors.forename: Junling
authors.initials: J
authors.lastname: Xing
mesh_terms: D015761:4-Aminopyridine / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D055592:Biophysical Phenomena / Q000187:drug effects / Q000502:physiology*; D004558:Electric Stimulation; D005260:Female; D066298:In Vitro Techniques; D007473:Ion Channels / Q000037:antagonists & inhibitors / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials / Q000502:physiology*; D008636:Mesencephalon / Q000166:cytology*; D009474:Neurons / Q000502:physiology*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D007473:Ion Channels; D026902:Potassium Channel Blockers; D011743:Pyrimidines; D026941:Sodium Channel Blockers; C082246:ICI D2788; D013779:Tetrodotoxin; D015761:4-Aminopyridine
keywords: 4-AP sensitive current; Excitability; Mesencephalic trigeminal; Persistent Na(+) current; Resonance