Time course of the changes of TH mRNA in rat brain and adrenal medulla after a single injection of reserpine.

Abstract

A single injection of reserpine causes a long lasting enhancement of the activity of tyrosine hydroxylase (TH), the enzyme catalyzing the rate‐limiting step in the biosynthesis of catecholamines. A sensitive method has been developed to assay both TH mRNA level and enzyme activity in tissue from a single rat. The time course of the induction was analysed in adrenals, locus coeruleus and substantia nigra. In both locus coeruleus and adrenals reserpine caused respectively 4.2‐ and 4.5‐fold increase of TH mRNA which was maximal 2 days after drug injection. This increase is about twice that of the enzyme activity. No change was observed in substantia nigra. The effect lasted longer in locus coeruleus than in adrenal. In the latter, TH mRNA had almost returned to initial values at day 4 whereas at this time it is 3‐fold higher in locus coeruleus and still significant at day 18. This result suggests that induction of TH results from an enhanced transcription of the TH gene. The time course difference between locus coeruleus and adrenals is most likely to result from a difference in the stability of TH mRNA in the two structures.

Differential Role of Galanin Receptors in the Regulation of Depression-Like Behavior and Monoamine/Stress-Related Genes at the Cell Body Level

“…The stressful event (forced swimming) combined with repeated i.p. injections resulted in increased activity of the LC NA system, evidenced by an increase of TH and galanin mRNA levels in the LC, in agreement with previous findings (Biguet et al, 1986;Berod et al, 1987;Richard et al, 1988;Austin et al, 1990;Holmes et al, 1995). Stress-induced hyperactivity of the LC neurons and increased release of NA have been proposed to contribute to development of human depression (Nestler et al, 1990; see Mongeau et al, 1997;Grant and Weiss, 2001;Morilak and Frazer, 2004).…”

Multiple Protein Factors Interact with the cis-Regulatory Elements of the Proximal Promoter in a Cell-Specific Manner and Reg\ ulate Transcription of the Dopamine b-Hydroxylase Gene

“…Among several genes specifically expressed in noradrenergic neurons, dopamine ␤-hydroxylase (DBH; EC 1.14.17.1) is a hallmark protein, because noradrenaline is synthesized by this enzyme (Kirshner and Goodall, 1957;Friedman and Kaufman, 1965). Regulation of the DBH gene provides a challenging system for studying neuron-specific gene regulation in general, as well as cell type-specific gene expression in the brain, for the following reasons: (1) DBH is expressed restrictively in noradrenergic and adrenergic neurons and neurosecretary cells in the nervous system; (2) differential expression of DBH among catecholaminergic neurons underlies phenotypic subspecifications among catecholaminergic neurons; that is, whereas tyrosine hydroxylase (TH) is expressed both in dopaminergic and noradrenergic neurons, DBH is expressed only in noradrenergic neurons; and (3) expression of DBH is modulated in response to a variety of trans-synaptic signals, hormones, growth factors, and stress (Otten and Thoenen, 1976;Sabban et al, 1983;Acheson et al, 1984;Faucon Biguet et al, 1986;Lewis et al, 1987;Badoyannis et al, 1991;McMahon et al, 1992; K. T. Lamouroux et al, 1993;Wessel and Joh, 1993).…”

Regulation of Tyrosine Hydroxylase Gene Expression by Muscarinic Agonists in Rat Adrenal Medulla

“…The increases in adrenal TH protein elicited by these stimuli are usually preceded by induction of TH mRNA and stimulation of TH gene transcription rate (Tank et al, 1985;Faucon Biguet et al, 1986;Fossom et al, 1991a;Osterhout et al, 1997). These responses are also usually dependent on presynaptic innervation of the adrenal medulla and hence are mediated by transsynaptic mechanisms Kvetnansky et al, 1971;Fluharty et al, 1983;Stachowiak et al, 1985Stachowiak et al, , 1986.…”