Variation in sodium current amplitude between vasopressin and oxytocin hypothalamic supraoptic neurons

Reese Scroggs, Lie Wang, Ryoichi Teruyama, William Armstrong

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Biophysical characteristics of tetrodotoxin-sensitive sodium (Na+) currents were studied in vasopressin (VP) and oxytocin (OT) supraoptic neurons acutely isolated from rat hypothalamus. Na+ current density (pA/pF) was significantly greater in VP neurons than in OT neurons. No significant difference between VP and OT neurons was detected regarding the voltage dependence of activation and steady-state inactivation, or rate of recovery from inactivation of Na+ currents. In both VP and OT neurons, the macroscopic inactivation of the Na+ currents was best fitted with a double-exponential expression suggesting two rates of inactivation. Also in both types, the time course of recovery from inactivation proceeded with fast and slow time constants averaging around 8 and 350 ms, respectively, suggesting the presence of multiple pathways of recovery from inactivation. The slower time constant of recovery of inactivation may be involved in the decrease in action potential (AP) amplitude that occurs after the first spike during burst firing in both neuronal types. The larger amplitude of Na+ currents in VP vs. OT neurons may explain the previous observations that VP neurons exhibit a lower AP threshold and greater AP amplitude than OT neurons, and may serve to differently tune the firing properties and responses to neuromodulators of the respective neuronal types.

Original languageEnglish (US)
Pages (from-to)1017-1024
Number of pages8
JournalJournal of neurophysiology
Volume109
Issue number4
DOIs
StatePublished - Feb 15 2013

Fingerprint

Oxytocin
Vasopressins
Sodium
Neurons
Action Potentials
Tetrodotoxin
Hypothalamus
Neurotransmitter Agents

All Science Journal Classification (ASJC) codes

  • Physiology
  • Neuroscience(all)

Cite this

Variation in sodium current amplitude between vasopressin and oxytocin hypothalamic supraoptic neurons. / Scroggs, Reese; Wang, Lie; Teruyama, Ryoichi; Armstrong, William.

In: Journal of neurophysiology, Vol. 109, No. 4, 15.02.2013, p. 1017-1024.

Research output: Contribution to journalArticle

@article{3d893aef3ba84de6a49ef2786938f3a0,
title = "Variation in sodium current amplitude between vasopressin and oxytocin hypothalamic supraoptic neurons",
abstract = "Biophysical characteristics of tetrodotoxin-sensitive sodium (Na+) currents were studied in vasopressin (VP) and oxytocin (OT) supraoptic neurons acutely isolated from rat hypothalamus. Na+ current density (pA/pF) was significantly greater in VP neurons than in OT neurons. No significant difference between VP and OT neurons was detected regarding the voltage dependence of activation and steady-state inactivation, or rate of recovery from inactivation of Na+ currents. In both VP and OT neurons, the macroscopic inactivation of the Na+ currents was best fitted with a double-exponential expression suggesting two rates of inactivation. Also in both types, the time course of recovery from inactivation proceeded with fast and slow time constants averaging around 8 and 350 ms, respectively, suggesting the presence of multiple pathways of recovery from inactivation. The slower time constant of recovery of inactivation may be involved in the decrease in action potential (AP) amplitude that occurs after the first spike during burst firing in both neuronal types. The larger amplitude of Na+ currents in VP vs. OT neurons may explain the previous observations that VP neurons exhibit a lower AP threshold and greater AP amplitude than OT neurons, and may serve to differently tune the firing properties and responses to neuromodulators of the respective neuronal types.",
author = "Reese Scroggs and Lie Wang and Ryoichi Teruyama and William Armstrong",
year = "2013",
month = "2",
day = "15",
doi = "10.1152/jn.00812.2012",
language = "English (US)",
volume = "109",
pages = "1017--1024",
journal = "Journal of Neurophysiology",
issn = "0022-3077",
publisher = "American Physiological Society",
number = "4",

}

TY - JOUR

T1 - Variation in sodium current amplitude between vasopressin and oxytocin hypothalamic supraoptic neurons

AU - Scroggs, Reese

AU - Wang, Lie

AU - Teruyama, Ryoichi

AU - Armstrong, William

PY - 2013/2/15

Y1 - 2013/2/15

N2 - Biophysical characteristics of tetrodotoxin-sensitive sodium (Na+) currents were studied in vasopressin (VP) and oxytocin (OT) supraoptic neurons acutely isolated from rat hypothalamus. Na+ current density (pA/pF) was significantly greater in VP neurons than in OT neurons. No significant difference between VP and OT neurons was detected regarding the voltage dependence of activation and steady-state inactivation, or rate of recovery from inactivation of Na+ currents. In both VP and OT neurons, the macroscopic inactivation of the Na+ currents was best fitted with a double-exponential expression suggesting two rates of inactivation. Also in both types, the time course of recovery from inactivation proceeded with fast and slow time constants averaging around 8 and 350 ms, respectively, suggesting the presence of multiple pathways of recovery from inactivation. The slower time constant of recovery of inactivation may be involved in the decrease in action potential (AP) amplitude that occurs after the first spike during burst firing in both neuronal types. The larger amplitude of Na+ currents in VP vs. OT neurons may explain the previous observations that VP neurons exhibit a lower AP threshold and greater AP amplitude than OT neurons, and may serve to differently tune the firing properties and responses to neuromodulators of the respective neuronal types.

AB - Biophysical characteristics of tetrodotoxin-sensitive sodium (Na+) currents were studied in vasopressin (VP) and oxytocin (OT) supraoptic neurons acutely isolated from rat hypothalamus. Na+ current density (pA/pF) was significantly greater in VP neurons than in OT neurons. No significant difference between VP and OT neurons was detected regarding the voltage dependence of activation and steady-state inactivation, or rate of recovery from inactivation of Na+ currents. In both VP and OT neurons, the macroscopic inactivation of the Na+ currents was best fitted with a double-exponential expression suggesting two rates of inactivation. Also in both types, the time course of recovery from inactivation proceeded with fast and slow time constants averaging around 8 and 350 ms, respectively, suggesting the presence of multiple pathways of recovery from inactivation. The slower time constant of recovery of inactivation may be involved in the decrease in action potential (AP) amplitude that occurs after the first spike during burst firing in both neuronal types. The larger amplitude of Na+ currents in VP vs. OT neurons may explain the previous observations that VP neurons exhibit a lower AP threshold and greater AP amplitude than OT neurons, and may serve to differently tune the firing properties and responses to neuromodulators of the respective neuronal types.

UR - http://www.scopus.com/inward/record.url?scp=84874060152&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84874060152&partnerID=8YFLogxK

U2 - 10.1152/jn.00812.2012

DO - 10.1152/jn.00812.2012

M3 - Article

VL - 109

SP - 1017

EP - 1024

JO - Journal of Neurophysiology

JF - Journal of Neurophysiology

SN - 0022-3077

IS - 4

ER -