Journal article
Tissue-specific noradrenergic activity during acute heat stress in rats
Journal of applied physiology (1985), Vol.74(4), pp.1988-1993
04/01/1993
DOI: 10.1152/jappl.1993.74.4.1988
PMID: 8514720
Abstract
The purpose of this study was to determine whether nonexertional heat stress alters the behavior of internal organ and skeletal muscle sympathetic nervous system (SNS) activity in unrestrained conscious rats. Norepinephrine (NE) synthesis was blocked with alpha-methyl-p-tyrosine, and the rate of decline in tissue NE concentration after synthesis blockade was used to estimate SNS activity in the left ventricle, kidney, liver, adrenal gland, and soleus and extensor digitorum longus muscles of the hindlimb. Male Sprague-Dawley rats (250–320 g) were maintained in thermoneutral control conditions (ambient temperature = 24 degrees C, n = 10) or exposed to an ambient temperature of 42 degrees C until a colonic temperature (Tc) of 39.5 or 41.0 degrees C (n = 10 each) was attained. During heating, as Tc rose from control levels (approximately 38 degrees C) to 41.0 degrees C, mean arterial pressure and heart rate increased from 120 +/- 3 to 141 +/- 3 mmHg and from 381 +/- 4 to 420 +/- 5 beats/min, respectively (P < 0.05). There was a strong trend for increased NE turnover rates in the left ventricle, liver, and adrenal gland in NE synthesis-blocked rats attaining a Tc of 39.5 degrees C compared with the normothermic values, whereas the turnover rate in the kidney was significantly elevated at this level of hyperthermia (126%) vs. the control condition. In animals heated to a Tc of 41.0 degrees C, the NE turnover rate was markedly increased in the left ventricle (590%), kidney (531%), liver (262%), and adrenal gland (602%) compared with normothermic control values.
Details
- Title: Subtitle
- Tissue-specific noradrenergic activity during acute heat stress in rats
- Creators
- Kevin C Kregel - Department of Exercise and Sport Sciences, University of Arizona, Tucson 85721David G Johnson - Department of Exercise and Sport Sciences, University of Arizona, Tucson 85721Douglas R Seals - Department of Exercise and Sport Sciences, University of Arizona, Tucson 85721
- Resource Type
- Journal article
- Publication Details
- Journal of applied physiology (1985), Vol.74(4), pp.1988-1993
- DOI
- 10.1152/jappl.1993.74.4.1988
- PMID
- 8514720
- ISSN
- 8750-7587
- eISSN
- 1522-1601
- Language
- English
- Date published
- 04/01/1993
- Academic Unit
- Radiation Oncology; Provost Office Administration; Health and Human Physiology
- Record Identifier
- 9984213453002771
Metrics
7 Record Views