Angiotensin AT1 receptor subtypes AT1A and AT1B mRNAs are expressed in tyrosine hydroxylase immunoreactive (TH‐ir) neurons in the rat caudal nucleus of the solitary tract (NTS)

Abstract

Identifying the gene expression profiles in cells in the caudal NTS is a major challenge due to the heterogeneity of cellular populations in this region. We utilized quick immunohistochemical labeling coupled with laser capture microdissection to identify and capture TH‐ir neurons from the caudal NTS. Six groups of 10–13 TH‐ir caudal NTS neurons were captured from adult, male Sprague‐Dawley rats and total RNA was extracted from each group. mRNA levels of TH and the angiotensin II receptor subtypes AT1A and AT1B were assessed by quantitative real time reverse transcription polymerase chain reaction using GAPDH as the housekeeping gene. The 2−ΔCt for TH averaged .171 ± .028. mRNA of both AT1A and AT1B subtypes of the angiotensin AT1 receptor was expressed in the TH neurons. The 2−ΔCt for AT1A and AT1B averaged .023 ± .004 and .025 ± .003 respectively. Our data show the existence of AT1A and AT1B receptor subtype mRNAs in catecholaminergic neurons in the caudal NTS.