Laser capture microdissection of spinally‐projecting RVLM neurons: Analysis of NMDA receptor subunit gene expression.

Abstract

Spinally‐projecting neurons in the rostral ventrolateral medulla (RVLM) are important in blood pressure regulation. Functional and anatomical studies suggest that N‐methyl‐D‐aspartate receptors (NMDARs) are located in the RVLM and play important roles in cardiovascular reflexes. Since NMDARs are also associated with neuroplasticity, we determined the feasibility of comparing NMDAR subunit gene expression in the RVLM. To test this, Fluorogold (FG) was injected into the intermediolateral cell column of Sprague Dawley rats (n=4) to label spinally‐projecting neurons. After 1–2 wks, FG‐labeled cells were obtained under RNAase free conditions from fresh, frozen sections (8 μm) using laser capture microdissection (Arcturus PixCell II). Total mRNA was isolated, and NMDAR subunits (NR1 and NR2A) and GAPDH were quantified by real time PCR (qRT‐PCR) using Taqman probes. Preliminary findings suggest that we are able to detect NMDAR subunit gene expression in spinally‐projecting RVLM neurons. Alterations in NMDAR number or subunit composition may influence the excitability of RVLM neurons and contribute to changes in sympathetic outflow in physiological and pathophysiological states. Future studies will compare physical activity‐related changes in gene and protein expression levels of NMDAR subunits. (AHA# 09PRE2050230 and HL‐089364)