Functional analysis of GABAA receptors in nucleus tractus solitarius neurons from neonatal rats

Ren Qi Huang, Glenn H. Dillon

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

To gain insight into specific GABAA receptor configurations functionally expressed in the nucleus tractus solitarius (NTS), we conducted several physiological and pharmacological assessments. NTS neurons were characterized in thin brain slices from 1-14 day old rats using whole-cell patch clamp recordings. GABAA- receptor-mediated currents were detected in all neurons tested, with an average EC50 of 22.2 μM. GABA currents were consistently stimulated by diazepam (EC50=63 nM), zolpidem (EC50=85 nM), loreclezole (EC50=10.1 μM) and the neurosteroid 5α-pregnan-3α-hydroxy-20-one (3α-OH-DHP). In contrast, GABA-gated currents of the NTS were inhibited by the divalent cation Zn2+ (IC50=33.6 μM) picrotoxin (IC50=2.4 μM) and blockade of endogenous protein tyrosine kinase. GABA-activated currents were insensitive to furosemide (10-1000 μM) in all NTS neurons tested. Collectively, the data suggest that in neonatal rats, the predominant α subunit isoform present in GABAA receptors of the NTS appears to be the α1 and/or α2 subunit. β2 and/or β3 subunits are the major β isoform, while the predominant γ subunit is likely γ2. Our data suggest the contribution to NTS GABA currents by α3-α6, β1, γ1 and δ subunits, if present, is minor by comparison.

Original languageEnglish
Pages (from-to)183-194
Number of pages12
JournalBrain Research
Volume921
Issue number1-2
DOIs
StatePublished - 7 Dec 2001

Keywords

  • Brainstem
  • GABA receptor
  • Nucleus tractus solitarius
  • Tyrosine kinase

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