CARDIOVASCULAR EFFECTS OF NOREPINEPHRINE THERMO GENESIS IN WARM- AND COLD-ACCLIMATIZED RATS,
Abstract
The cardiovascular and metabolic actions of nore pinephrine (NE) and their interrelationships were studied at normal room temperature in anesthe tized, warm-acclimatized (W-A) (26 = 1 C) and cold-acclimatized (C-A) (3 = 1 C) rats. Norepine phrine caused a greater increase in the cardiac output, heart rate, stroke volume and right atri al 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 pres sure 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 prein fusion 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 sys temic resistance to actively metabolizing areas. (i.e. the viscera). (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1962
- Accession Number
- AD0410779
Entities
People
- Eugene Evonuk
- John P. Hannon