Unique levels of expression of N-methyl-D-aspartate receptor subunits and neuronal nitric oxide synthase in the rostral ventrolateral medulla of the spontaneously hypertensive rat

Mark A. Edwards, Rhonda A. Loxley, Kellysan Powers-Martin, Janusz Lipski, Douglas J. McKitrick, Leonard F. Arnolda, Jacqueline K. Phillips*

*Corresponding author for this work

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

The rostral ventrolateral medulla (RVLM) is the major brainstem region contributing to sympathetic control of blood pressure. We have compared the expression of N-methyl-D-aspartate (NMDA) receptor subunits (NR1, NR2A-D), NR1 splice variants (NR1-1a/1b, -2a/2b, -3a/3b, -4a/4b), and the neuronal and inducible isoforms of NO synthase (nNOS and iNOS) in the RVLM of Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR), based on the hypothesis that altered NMDA receptor make-up or altered expression of endogenous NO may be associated with the increase in sympathetic output described from this site in hypertension. Total RNA was extracted and reverse transcribed from the RVLM of mature male WKY and SHR (16-23 weeks). Conventional polymerase chain reaction (PCR) indicated that only the NR1 splice variants NR1-2a, NR1-2b, NR1-4a and NR1-4b were expressed in the RVLM of either species. Quantitative real-time PCR indicated that for both strains of rat, mRNA for the NR1 subunit (all splice variants) was the most abundant (16.5-fold greater, P≤0.05, relative to the NR2A subunit). Amongst the NR2A-D subunits, NR2C was the most abundant (7- and 1.7-fold greater relative to the NR2A subunit, P≤0.05, WKY and SHR, respectively). Relative to WKY, mRNA levels for the NR2C and NR2D subunits in the SHR RVLM were significantly lower (0.3- and 0.25-fold less, P≤0.05), while nNOS was significantly higher (1.76-fold greater, P≤0.05). This was confirmed immunohistochemically for nNOS expression. These results demonstrate differential expression levels of NMDA receptor subunits and NOS isoforms in the RVLM region of SHR when compared to WKY rats.

Original languageEnglish
Pages (from-to)33-43
Number of pages11
JournalMolecular Brain Research
Volume129
Issue number1-2
DOIs
Publication statusPublished - 22 Oct 2004
Externally publishedYes

Keywords

  • Autonomic
  • Excitatory amino acid receptors: structure, function and expression
  • Hypertension
  • mRNA
  • Neuronal nitric oxide synthase (nNOS)
  • Neurotransmitters, modulators, transporters and receptors
  • NMDA receptor splice variants
  • Real-time PCR

Fingerprint Dive into the research topics of 'Unique levels of expression of N-methyl-D-aspartate receptor subunits and neuronal nitric oxide synthase in the rostral ventrolateral medulla of the spontaneously hypertensive rat'. Together they form a unique fingerprint.

Cite this