Comments

Vasopressin(VP) magnocellular neurons in the SON and PVN express all the three α,βandγsubunits of epithelial Na+ channel(ENaC); however, the effect of dietary salt intake on ENaC regulation and activity in VP neurons remains unclear.In this work, the authors found that high dietary salt intake caused an increase in the expression and activity of ENaC which resulted in the steady state depolarization of VP neurons. Understandings of the brain structures that mediate ENaC regulation of blood pressure and the regulation and activity of ENaC in VP neurons is helpful for identification of novel target of controlling hypertension and hydromineral balance.

 

Questions:

1)      What is the influence on ENaC activity when high dietary salt intake increased the expression of β- and γ-ENaC subunits in the SON and the translocation of α-ENaC subunit towards the plasma membrane?

2)      How did high dietary salt intake increase mean amplitude of the putative ENaC currents in VP neurons?

3)      According to the study by Kim and colleagues, prolonged salt water intake will cause reversal of EGABA and make the membrane more depolarized? Under this condition, will ENaC-mediated synaptic drive further contribute to the excitability of VP neurons or cause inactivation of voltage-gated Na+ channels?

4)      What is the special value to measure ENaC subunit distribution at submembrane area and in the cytosol?

5)      How did ENaC activity link with the action of Dynorphin?

6)      What is influence of synaptic inputs versus intrinsic factors on the Phasic firing pattern?

7)      What are the ion currents responsible for different phases of an action potential in VP neurons, e.g., depolarization, AHP, ADP and repolarization?

8)      Why did the authors argue for that ENaCs appear to have only a minor role in the regulation of the firing activity of VP neurons in the absence of synaptic inputs?


2018年02月05日

2018-1-30 Literature Analysis

Sharma et al. Effect of dietary salt intake on epithelial Na+ channels(ENaC) in vasopressin magnocellular neurosecretory neurons in the rat supraoptic nucleus. J Physiol 595.17 (2017) pp 5857–5874. Presented by Yang Liu.

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