Stress increases gene expression of phenylethanolamine N-methyltransferase in spleen of rats via pituitary-adrenocortical mechanism☆
Introduction
Phenylethanolamine N-methyltransferase (PNMT) catalyses the final step in the catecholamine biosynthetic pathway converting norepinephrine (NE) to epinephrine (EPI). Although the adrenal medulla is the primary source of EPI, extra-adrenal sources of EPI have been reported. Kvetnansky et al. (1979) found a slight but significant elevation of plasma EPI levels in adrenal medullectomized rats during stress exposure. Humans after adrenalectomy maintained nearly normal levels of urinary EPI (von Euler et al., 1961). In small concentrations, EPI was found almost in all organs of the body (Caramona and Soares-da-Silva, 1985).
PNMT activity has also been detected besides the adrenal medulla in other organs of rats and humans, e.g. in brain stem, heart, lungs, spleen, skeletal muscles, etc. (Pendleton et al., 1978, Kennedy et al., 1995). A significant overall correlation occurred between tissue PNMT activity and EPI levels (Kennedy et al., 1995). Detection of PNMT mRNA in lungs (Kennedy et al., 1993), embryonic (Ebert et al., 1996) and adult hearts (Kvetnansky et al., 1998a), in brain areas as brainstem (Evinger et al., 1992, Shuh et al., 1994), limbic system (Mezey, 1989), hypothalamus and cerebellum (Andreassi et al., 1998b) of rats confirms that the PNMT gene is expressed also in nonadrenal tissues. The recent data have shown that PNMT gene is also expressed in lymphoid tissues such as spleen and thymus (Andreassi et al., 1998a). The ratio of PNMT mRNA levels in adrenal medulla to that in spleen is approximately 200-fold (Andreassi et al., 1998a) which is also the ratio in PNMT activity previously reported for these tissues (Pendleton et al., 1978).
Immobilization (IMO) is a severe stressor which activates both adrenomedullary and sympathoneural systems (Kvetnansky et al., 1998b). In the adrenal medulla, a single IMO for two hours produced several fold increased PNMT mRNA levels (Viskupic et al., 1994). This effect was more pronounced by repeated IMO, which produced even a significant elevation of adrenal medullary, PNMT activity (Kvetnansky et al., 1970, Viskupic et al., 1994). Regulation of PNMT activity and gene expression in adrenal medulla is predominantly regulated by glucocorticoids (Viskupic et al., 1994, Kvetnansky et al., 1995, Sabban and Kvetnansky, 2001).
The aim of the present study was to confirm the PNMT gene expression in the spleen of control rats as well as to determine if PNMT gene expression is affected by single or repeated immobilization stress.
Section snippets
Animals
Adult male Sprague-Dawley rats from Charles River Farm (Suzfeld, Germany), weighing 280–320 g, were used for the majority of experiments. Before initiation of experimental procedures, the animals were housed (3–4 per cage) for at least 7 days under light-controlled conditions (12 h light/dark cycle, light on at 0600 h) and room temperature 22±2°C. Food and water were available ad libitum.
In some experiments, bilaterally adrenalectomized (adrex), hypophysectomized (hypox), and appropriate
Presence and localization of PNMT gene expression in rat spleen
To identify the gene expression of PNMT in the spleen, two different approaches were used—Northern blot and hybridization with PNMT probe and PCR (Fig. 1). As a positive control, rat adrenal medulla (AM) was used for both methods. By Northern blot analysis (Fig. 1, upper part) we observed a signal of PNMT mRNA only for AM, while no signal occurred in the spleen (S). However, besides AM, gene expression of PNMT was detected in spleen of control and/or immobilized rats (Fig. 1, middle part) where
Presence and localization of PNMT gene expression in rat spleen
In the present study we confirmed the finding of Andreassi et al. (1998a) that the PNMT gene is expressed in rat spleen. To ensure that the obtained PCR fragment is really derived from PNMT we checked the PNMT-specific mRNA amplification product after gel electrophoresis by Southern blot analysis. Hybridization with the PNMT cDNA probe indicated that the PCR fragments observed in spleen of control as well as stressed rats were derived from the same PNMT transcript as in the adrenal medulla.
Acknowledgements
The presented study was supported by the grant of the Slovak Grant Agency VEGA (2/6109), EU Center of Excellence Support ICA1-CT-2000-70008 and the Fogarty Collaborative Research Award (1R03TW00984). Authors wish to thank Mrs. D. Chalupkova and Mrs. D. Janovova for their excellent technical assistance.
References (39)
- et al.
Phenylethanolamine N-methyltransferase mRNA in rat spleen and thymus
Neurosci. Lett.
(1998) - et al.
Catecholamine-induced leukocytosis: early observations, current research, and future direction
Brain Behav. Immunol.
(1996) - et al.
A radiometric assay for phenylethanolamine-N-methyltransferase and catechol-O-methyltransferase in a single tissue sample: Application to rat hypothalamic nuclei, pineal gland and heart
Anal. Biochem.
(1987) - et al.
Expression of phenylethanolamine N-methyltransferase in the embryonic rat heart
J. Mol. Cell. Cardiol.
(1996) - et al.
Expression and in vivo modulation of alpha and β-adrenoceptors on human natural killer (CD16+) cells
J. Neuroimmunol.
(1997) - et al.
Ontogeny of epinephrine metabolic pathways in the rat: role of glucocorticoids
Int. J. Dev. Neurosci.
(2000) - et al.
Differentiation of receptors responsive to isoproterenol
Life Sci.
(1967) - et al.
Adrenergic projections from lower brainstem to the hypothalamic paraventricular nucleus, the lateral hypothalamic area and the central nucleus of the amygdala in rats
J. Chem. Neuroanat.
(1992) - et al.
Stress-triggered activation of gene expression in catecholaminergic systems: dynamics of transcriptional events
Trends Neurosci.
(2001) The role of adrenoceptor-mediated signals in the modulation of lymphocyte function
Adv. Neuroimmunol.
(1995)
Restoration of sympathetic noradrenergic nerve fibers in the spleen by low doses of L-deprenyl treatment in young sympathectomized and old Fischer 344 rats
J. Neuroimmunol.
Phenylethanolamine N-methyltransferase gene expression: synergistic activation by Egr-1, AP2 and the glucocorticoid receptor
Mol. Brain Res.
In situ hybridization histochemical detection of neuropeptide mRNA using DNA and RNA probes
Methods Enzymol.
Phenylethanolamine N-methyltransferase mRNA in rat hypothalamus and cerebellum
Brain Res.
Neuroimmune mechanisms in health and disease: 1. Health
Can. Med. Assoc. J.
Immune-neuro-endocrine interactions: facts and hypotheses
Endocr. Rev.
Spatial and temporal expression of alpha- and -βthyroid hormone receptor mRNAs including the β2-subtype, in the developing mammalian nervous system
J. Neurosci.
The effects of chemical sympathectomy on dopamine, noradrenaline and adrenaline content in some peripheral tissues
British J. Pharmacol.
The sympathetic nerve – An integrative interface between two supersystems: The brain and the immune system
Pharmacol. Rev.
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This paper is dedicated to the memory of our good friends Prof. Bela Bohus from Groningen and Prof. Eugen Naumenko from Novosibirsk as well as to our close coworker Dr. Janka Jelokova from Bratislava.