Journal article
Influence of aging on tissue-specific noradrenergic activity at rest and during nonexertional heating in rats
Journal of applied physiology (1985), Vol.76(3), pp.1226-1231
03/1994
DOI: 10.1152/jappl.1994.76.3.1226
PMID: 7911798
Abstract
The purpose of this study was to test the hypothesis that sympathetic nervous system (SNS) activity to internal organs during nonexertional heat stress is exaggerated with advancing age. Norepinephrine (NE) synthesis was blocked with alpha-methyl-DL-p-tyrosine, and NE turnover rates were determined in the left ventricle, renal cortex, liver, and adrenal gland in groups of conscious unrestrained mature (12-mo-old) and senescent (24-mo-old) Fischer 344 rats before and after whole body heating. Animals were maintained in thermoneutral control conditions (n = 10 per group) or exposed to an ambient temperature of 42 degrees C until colonic temperature (TCO) reached a designated level (39.5 or 41.0 degrees C; n = 10 per group at both temperature levels). NE turnover rates were similar in all four tissues sampled for both mature and senescent rats in the resting condition. Over the course of the heating period, progressive increases in arterial blood pressure and heart rate were observed, with the magnitudes of the pressor and tachycardic responses similar between age groups. At TCO of 39.5 degrees C, calculated NE turnover rates were unchanged from control levels for the senescent and mature animals, whereas animals heated to 41.0 degrees C demonstrated marked elevations in NE turnover in all four tissues for both age groups. In addition, the increase in NE turnover rate at this TCO was significantly higher for senescent rats compared with their younger counterparts in the renal cortex (410 vs. 278%) and liver (557 vs. 170%).
Details
- Title: Subtitle
- Influence of aging on tissue-specific noradrenergic activity at rest and during nonexertional heating in rats
- Creators
- Kevin C Kregel - Department of Exercise and Sport Sciences, University of Arizona, Tucson 85721
- Resource Type
- Journal article
- Publication Details
- Journal of applied physiology (1985), Vol.76(3), pp.1226-1231
- DOI
- 10.1152/jappl.1994.76.3.1226
- PMID
- 7911798
- NLM abbreviation
- J Appl Physiol (1985)
- ISSN
- 8750-7587
- eISSN
- 1522-1601
- Grant note
- AG-12350 / NIA NIH HHS HL-07249 / NHLBI NIH HHS GM-08400 / NIGMS NIH HHS
- Language
- English
- Date published
- 03/1994
- Academic Unit
- Radiation Oncology; Provost Office Administration; Health, Sport, and Human Physiology
- Record Identifier
- 9984213310402771
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