AT1a influences GABAA-mediated inhibition through regulation of KCC2 expression

George E. Farmer, Kirthikaa Balapattabi, Martha E. Bachelor, Joel T. Little, J. Thomas Cunningham

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The median preoptic nucleus (MnPO) is an integrative site involved in body fluid homeostasis, cardiovascular control, thermoregulation, and sleep homeostasis. Angiotensin II (ANG II), a neuropeptide shown to have excitatory effects on MnPO neurons, is of particular interest with regard to its role in body fluid homeostasis and cardiovascular control. The present study investigated the role of angiotensin type 1a (AT1a) receptor activation on neuronal excitability in the MnPO. Male Sprague-Dawley rats were infused with an adeno-associated virus with an shRNA against the AT1a receptor or a scrambled control. In vitro loose-patch voltage-clamp recordings of spontaneous action potential activity were made from labeled MnPO neurons in response to brief focal application of ANG II or the GABAA receptor agonist muscimol. Additionally, tissue punches from MnPO were taken to asses mRNA and protein expression. AT1a receptor knockdown neurons were insensitive to ANG II and showed a marked reduction in GABAA-mediated inhibition. The reduction in GABAA-mediated inhibition was not associated with reductions in mRNA or protein expression of GABAA β-subunits. Knockdown of the AT1a receptor was associated with a reduction in the potassium-chloride cotransporter KCC2 mRNA as well as a reduction in pS940 KCC2 protein. The impaired GABAA-mediated inhibition in AT1a knockdown neurons was recovered by bath application of phospholipase C and protein kinase C activators. The following study indicates that AT1a receptor activation mediates the excitability of MnPO neurons, in part, through the regulation of KCC2. The regulation of KCC2 influences the intracellular [Cl] and the subsequent efficacy of GABAA-mediated currents.

Original languageEnglish
Pages (from-to)R972-R982
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume315
Issue number5
DOIs
StatePublished - Nov 2018

Fingerprint

Preoptic Area
Angiotensins
Angiotensin Type 1 Receptor
Neurons
Angiotensin II
Homeostasis
Body Fluids
Messenger RNA
GABA-A Receptor Agonists
Dependovirus
Muscimol
Proteins
Body Temperature Regulation
Equidae
Type C Phospholipases
Neuropeptides
Baths
Protein Kinase C
Small Interfering RNA
Action Potentials

Keywords

  • Angiotensin
  • KCC2
  • Median preoptic nucleus
  • ShRNA

Cite this

Farmer, George E. ; Balapattabi, Kirthikaa ; Bachelor, Martha E. ; Little, Joel T. ; Cunningham, J. Thomas. / AT1a influences GABAA-mediated inhibition through regulation of KCC2 expression. In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology. 2018 ; Vol. 315, No. 5. pp. R972-R982.
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AT1a influences GABAA-mediated inhibition through regulation of KCC2 expression. / Farmer, George E.; Balapattabi, Kirthikaa; Bachelor, Martha E.; Little, Joel T.; Cunningham, J. Thomas.

In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 315, No. 5, 11.2018, p. R972-R982.

Research output: Contribution to journalArticle

TY - JOUR

T1 - AT1a influences GABAA-mediated inhibition through regulation of KCC2 expression

AU - Farmer, George E.

AU - Balapattabi, Kirthikaa

AU - Bachelor, Martha E.

AU - Little, Joel T.

AU - Cunningham, J. Thomas

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