title: Stress triggered changes in expression of genes for neurosecretory granules in adrenal medulla.
abstract: With acute stress, the release of adrenomedullary catecholamines is important for handling the emergency situation. However, when chronic or repeated, stress alters the allostatic load and leads to a hyperadrenergic state, resulting in the development or worsening of a wide range of diseases. To help elucidate the mechanism, we examined the effects of single and repeated immobilization stress on gene expression of components of neurosecretory vesicles in the adrenal medulla. Male Sprague-Dawley rats were exposed to immobilization stress once for 2 h (1× IMO) or daily for six consecutive days (6× IMO). Compared to unstressed controls, 1× IMO elevated gene expression of vesicular monoamine transporter 2 (VMAT2). In response to 6× IMO, not only was VMAT2 mRNA still elevated, but chromogranin A (CgA) and chromogranin B (CgB) mRNAs were also increased two to three-fold above basal levels. To investigate the possible role of the hypothalamic-pituitary-adrenal axis in the induction of VMAT2, PC12 cells were treated with the synthetic glucocorticoid dexamethasone, which was found to elevate VMAT2 mRNA expression. The findings suggest that following repeated stress, elevations of various components of neurosecretory vesicles in the adrenal can facilitate more efficient utilization of the well-characterized heightened catecholamine levels.
authors.affiliation: Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA. Sabban@nymc.edu
authors.forename: Esther Louise
authors.initials: EL
authors.lastname: Sabban
authors.forename: Andrej
authors.initials: A
authors.lastname: Tillinger
authors.forename: Regina
authors.initials: R
authors.lastname: Nostramo
authors.forename: Lidia
authors.initials: L
authors.lastname: Serova
mesh_terms: D000313:Adrenal Medulla / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D003907:Dexamethasone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D005938:Glucocorticoids / Q000378:metabolism; D008297:Male; D009490:Neurosecretory Systems / Q000187:drug effects / Q000378:metabolism*; D016716:PC12 Cells; D051381:Rats; D017207:Rats, Sprague-Dawley; D022142:Secretory Vesicles / Q000187:drug effects / Q000378:metabolism*; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics*; D050493:Vesicular Monoamine Transport Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D005938:Glucocorticoids; C493451:Slc18a1 protein, rat; C493454:Slc18a2 protein, rat; D050493:Vesicular Monoamine Transport Proteins; D003907:Dexamethasone