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Electrophysiological Properties of Magno‐and Parvo‐Cellular Neurons in Rat Hypothalamic Paraventricular Nucleus
Author(s) -
Shen Yi Ming,
Lee So Yeong,
Han Seong Kyu,
Ryu Pan Dong
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.lb727
Subject(s) - parvocellular cell , electrophysiology , rostral ventrolateral medulla , medicine , nucleus , chemistry , neuroscience , spinal cord , endocrinology , neuron , hypothalamus , medulla oblongata , patch clamp , biology , central nervous system
The hypothalamic paraventricular nucleus (PVN) contains magnocellular neurosecretory neurons (PVN‐MC) projecting to posterior pituitary, and parvocellular neurons projecting to anterior pituitary (neurosecretory), medulla (PVN‐RVLM) and/or spinal cord (PVN‐IML) (presympathetic). These PVN neurons are different in their roles and projections, but the differences in excitability are not well known. In this study, we compared the basic electrophysiological properties of these neuron groups. The PVN‐MC, PVN‐IML and/or PVN‐RVLM neurons were identified by electrophysiological property (expressing a prominent transient outward rectification) and retrograde dye (FluoSphere‐Red). The spontaneous firing, EPSC and action potential were recorded in the cell‐attached or whole‐cell mode with Axopatch 200B. Data were sampled at 20 KHz using pClamp 8 data‐acquisition and analysis software. In the voltage clamp cell‐attached mode, the frequency of spontaneous firing in the PVN‐IML neurons was higher than those in the other two groups (PVN‐ RVLM, PVN‐IML, PVN‐MC: 1.4 vs. 2.8 vs. 1.0 Hz, n=30, 27, 29; p<0.05). The mean frequencies of IPSC (5.1Hz, n=11) was lowest and the 37~90% decay time of IPSC (5.6 ms, n=9) in PVN‐IML neurons was shortest, and the PVN‐MC neurons (191.0 mV n=12) had shown the largest amplitude of IPSC (PVN‐RVLM, PVN‐IML: 61 vs. 55 mV n=16, 11; p<0.05). The 37~90% decay time (5.8 ms, n=22) of EPSC in the PVN‐MC cells was also larger than those of the PVN‐RVLM and PVN‐IML neurons (3.2 vs. 2.88 ms, n=14, 16; p<0.05). The properties of action potential were determined in the whole cell current clamp. The amplitude in PVN‐MC was definitely the largest (PVN‐RVLM, PVN‐IML, PVN‐MC: 78 vs. 65 vs. 69 mV, n=20, 10, 17; p<0.05) These results indicate that electrophysiological properties of three neuron groups were also different. The PVN‐IML neurons were the highest of spontaneous firing, and PVN‐MC neurons have larger input resistance and action potential amplitude of action potential. Functional significance of these differences remains to be studied further.