Cardiovascular effects of norepinephrine thermogenesis in warm- and cold- acclimatized rats.

https://arctichealth.org/en/permalink/ahliterature298697
Source
Arctic Aeromedical Laboratory. Aerospace Medical Division, Air Force Systems Command. Fort Wainwright, Alaska. Technical documentary report TDR-62-51. 14 p.
Publication Type
Report
Date
March 1963
  1 document  
Author
Evonuk, Eugene
Hannon, John P.
Source
Arctic Aeromedical Laboratory. Aerospace Medical Division, Air Force Systems Command. Fort Wainwright, Alaska. Technical documentary report TDR-62-51. 14 p.
Date
March 1963
Language
English
Publication Type
Report
File Size
1599343
Physical Holding
University of Alaska Anchorage
Keywords
Animals
Rats
Cold Temperature
Exposure
Cardiovascular System
Metabolism
Levarterenol
Heat production (biology)
Abstract
The cardiovascular and metabolic actions of norepinephrine (NE} and their interrelationships were studied at normal room temperature in anesthetized, warm-acclimatized (W-A) (26° +/- 1° C) and cold-acclimatized (C-A) (3° +/- 1° C} rats. Norepinephrine caused a greater increase in the cardiac output, heart rate, stroke volume and right atrial pressure in the C-A animals than it did in the W-A animals. During the early metabolic response to NE (i. e. up to 25% increase in O2 consumption) there was a marked increase in the arterial pressure of both W-A and C-A rats, with the latter showing the greater maximum response. Beyond the 25% level of increased metabolism the arterial pressure and concomitantly the systemic resistance of the C-A animals declined sharply to the preinfusion levels, where they remained throughout the course of infusion. In contrast, the arterial pressure and systemic resistance of the W-A animals remained high. It was concluded that norepinephrine calorigenesis in the C-A rat is supported by an increased cardiac reserve capacity and an ability to preferentially reduce the systemic resistance to actively metabolizing areas (i.e. the viscera}.
Notes
UAA - ALASKA RC955.U9 no.62-51
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