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Age‐associated changes in mRNA levels of Phox2, norepinephrine transporter and dopamine β‐hydroxylase in the locus coeruleus and adrenal glands of rats
Author(s) -
Zhu MengYang,
Wang WeiPing,
Iyo Abiye H.,
Ordway Gregory A.,
Kim KwangSoo
Publication year - 2005
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2005.03245.x
Subject(s) - locus coeruleus , medicine , endocrinology , adrenal medulla , biology , in situ hybridization , catecholamine , messenger rna , norepinephrine , norepinephrine transporter , adrenal gland , gene expression , dopamine , gene , central nervous system , genetics
Age‐related changes in the gene expression of the transcription factors, Phox2a and 2b, and two marker proteins, norepinephrine transporter (NET) and dopamine β‐hydroxylase (DBH), of noradrenergic neurons were characterized in the locus coeruleus (LC) and adrenal glands using in situ hybridization. Analysis of changes was performed in rats that were 1–23 months of age. Compared to 1‐month‐old rats, there was a 62% increase of Phox2a messenger RNA (mRNA) in the LC of 3‐month‐old rats, and a decline of 37% in 23‐month‐old rats. In contrast, levels of Phox2b mRNA in the LC remained unchanged in 3‐month‐old rats, but declined to a 30% reduction in 23‐month‐old rats. Interestingly, mRNA levels of NET in the LC decreased with increasing age to a reduction of 29%, 30% and 43% in 3‐, 8‐ and 23‐month‐old rats, respectively. Similarly, DBH mRNA in the LC declined with increasing age to a 56% reduction in 23‐month‐old rats. mRNA levels of Phox2a, Phox2b, NET and DBH in the adrenal medulla of 23‐month‐old rats were significantly lower than those of 1‐month‐old rats. Semi‐quantitative reverse transcription assays of the same genes yielded data similar to in situ hybridization experiments, with β‐actin mRNA levels being unchanged across the ages. Taken together, these data reveal that reduced Phox2 mRNAs in the LC and adrenal medulla of aging rats are accompanied by a coincidental decline in mRNA levels of NET and DBH and suggest a possible relationship between Phox2 genes and the marker genes in noradrenergic neurons after birth.