Corticotrophin-releasing factor inhibits neuromedin U mRNA expressing neuron in the rat hypothalamic paraventricular nucleus in vitro.
In the present study, we examined the effects of corticotrophin-releasing factor (CRF) on neuromedin U (NMU) mRNA-expressing neurons in the rat paraventricular nucleus (PVN) by whole-cell patch-clamp recordings and single-cell reverse transcription-multiplex polymerase chain reaction (single-cell RT-mPCR) techniques. In total, of 116 PVN putative parvocellular neurons screened for NMU mRNA, 14.7% (17/116) of them expressed NMU mRNA. The electrophysiological properties observed in the NMU mRNA-expressing neurons were generation of a low-threshold Ca(2+) spike (LTS) and robust low voltage-activated (T-type) Ca(2+) currents. Under current-clamp conditions, CRF (100 nM) induced a reversible decrease in spike firing and significantly diminished the LTS in 88.2% (15/17) of NMU mRNA-expressing neurons. Extracellular application of 1 μM α-helical CRF-(9-14) (α-hCRF), a selective CRF receptor antagonist, completely blocked the CRF-induced decrease in spike firing in the NMU mRNA-expressing neurons. Under voltage-clamp conditions, CRF (100 nM) significantly decreased the peak value of the T-type Ca(2+) currents by 35.6±7.8%. These findings suggest that CRF decreases neuronal excitability and diminishes T-type Ca(2+) currents in a population of rat PVN NMU phenotype neurons in vitro.
Cellular Function Research Center, Yanbian University, 977, GongYuan Road, Yanji City, Jilin Province 133002, China.
Chun-Ping
CP
Chu
Chuan-Jie
CJ
Xu
Hiroshi
H
Kannan
De-Lai
DL
Qiu
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D046509:Tissue Culture Techniques
D009479:Neuropeptides; D012333:RNA, Messenger; C056900:neuromedin U; D003346:Corticotropin-Releasing Hormone