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Published on: March 3, 2021
Body fluid distribution in rats with cold-induced hypertension
1Department of Physiology, College of Medicine, University of Florida, Gainesville 32610, USA. ZSUN@PHYS.MED.UFL.EDU
Physiology & Behavior
|March 12, 1999
Summary
Chronic cold exposure in rats causes hypertension by increasing blood volume and peripheral resistance. While initial fluid volume expands, it normalizes by five weeks, suggesting dehydration develops.
Area of Science:
- Physiology
- Environmental Health
- Cardiovascular Science
Background:
- Chronic cold exposure is a known environmental stressor.
- Understanding cold-induced hypertension mechanisms is crucial for human health.
- Body fluid shifts are implicated in cardiovascular regulation.
Purpose of the Study:
- To investigate body fluid distribution during prolonged cold exposure.
- To elucidate the mechanisms underlying cold-induced hypertension.
- To assess the impact of cold on blood pressure and fluid volumes in rats.
Main Methods:
- Rats were exposed to cold (5°C) for 1, 3, and 5 weeks.
- Measurements included blood pressure (systolic, diastolic, mean), hematocrit, and fluid volumes (plasma, blood, extracellular).
- Thermogenic drinking behavior was also assessed upon return to warm conditions.
Main Results:
- Cold exposure significantly elevated blood pressure in a time-dependent manner.
- Diastolic blood pressure increase, indicating heightened peripheral vascular resistance, surpassed systolic increase.
- Plasma, blood, and extracellular fluid volumes initially increased but returned to baseline by week 5; hematocrit remained unchanged.
- Cold-exposed rats exhibited increased water intake (thermogenic drinking).
Conclusions:
- Cold-induced hypertension is linked to initial blood volume expansion.
- Sustained hypertension involves increased peripheral vascular resistance without persistent volume expansion.
- Prolonged cold exposure appears to induce dehydration in rats.
