Decreased stress responsivity of central and peripheral catecholaminergic systems in aged 344/N Fischer rats

Giovanni Cizza, Karel Pacak, Richard Kvetnansky, Miklos Palkovits, David S. Goldstein, Linda S. Brady, Koki Fukuhara, Ettore Bergamini, Irwin J. Kopin, Marc R. Blackman, George P. Chrousos, Philip W. Gold

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Abstract

We investigated the effects of stress on central and peripheral sympatho- adrenal and sympatho-neural functions in healthy, intact young (3-4 mo) and aged (24 mo) male Fischer 344/N rats. Extracellular fluid (ECF) levels of the catecholamines norepinephrine (NE), dihydroxyphenylglycol (DHPG), methoxyhydroxyphenylglycol (MHPG), and dihydroxyphenylacetic acid (DOPAC) were obtained by microdialysis in the paraventricular nucleus (PVN) of the hypothalamus at baseline and during immobilization (IMMO). The baseline levels of these substances were similar in both age groups, and their concentrations increased significantly in response to IMMO. The IMMO-induced increases of NE and MHPG, however, were significantly smaller in old than in young rats. Plasma levels of the catecholamines NE, DHPG, MHPG, DOPAC, dihydroxyphenylalanine (DOPA), epinephrine (EPI), dopamine (DA), and HVA were also determined in young and old rats during IMMO. Basal levels of these substances were significantly higher in old than in young rats. The magnitude of the IMMO-induced increases in the majority of these compounds however, was significantly smaller in old than in young rats. We conclude that, at the basal state, aging in the Fischer rat is associated with normal PVN ECF, but high plasma catecholamine levels; at stress state, however, old rats have substantially lesser activation of their central and peripheral catecholaminergic systems than young rats.

Original languageEnglish
Pages (from-to)1217-1224
Number of pages8
JournalJournal of Clinical Investigation
Volume95
Issue number3
DOIs
Publication statusPublished - Mar 1995

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ASJC Scopus subject areas

  • Medicine(all)

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Cizza, G., Pacak, K., Kvetnansky, R., Palkovits, M., Goldstein, D. S., Brady, L. S., Fukuhara, K., Bergamini, E., Kopin, I. J., Blackman, M. R., Chrousos, G. P., & Gold, P. W. (1995). Decreased stress responsivity of central and peripheral catecholaminergic systems in aged 344/N Fischer rats. Journal of Clinical Investigation, 95(3), 1217-1224. https://doi.org/10.1172/JCI117771