Effects of dehydration on the vasopressin response to immersion
| Autor: | Karl Kirsch, L. Röcker, H. von Ameln, M. Laniado |
|---|---|
| Rok vydání: | 1985 |
| Předmět: |
Adult
Hyperthermia medicine.medical_specialty Vasopressin Mean arterial pressure Supine position Physiology Blood Pressure Body Temperature Heart Rate Physiology (medical) Internal medicine Hypovolemia Immersion medicine Humans Dehydration Blood Volume Chemistry Body Weight Osmolar Concentration Blood Proteins medicine.disease Arginine Vasopressin Plasma osmolality Endocrinology medicine.symptom Hypervolemia |
| Zdroj: | Journal of Applied Physiology. 58:114-120 |
| ISSN: | 1522-1601 8750-7587 |
| DOI: | 10.1152/jappl.1985.58.1.114 |
| Popis: | Nine healthy volunteers underwent three experimental procedures in random order. The protocols were 4 h of thermal dehydration followed by 2 h of head-out water immersion, 4 h of thermal dehydration followed by 2 h of chair rest, and 6 h of rest in the supine position. Four hours of heat exposure (50 degrees C) resulted in a body weight loss of approximately 3.5%. Plasma osmolality rose by approximately 5 mosmol/kg, mean arterial pressure (MAP) decreased from 85 to 78 mmHg, and body temperature increased from 36.8 to 38.6 degrees C. As a consequence of the combined action of hypertonicity, hypovolemia, hypotension, and hyperthermia, plasma arginine vasopressin (AVP) increased from 2.1 to 8.1 pg/ml after 4 h thermal dehydration. Changes in body weight, plasma osmolality, body temperature, and MAP were similar after either a subsequent 2 h of water immersion or 2 h of chair rest. However, during chair rest plasma AVP remained elevated (8.4 pg/ml), whereas during immersion plasma AVP decreased from 8.1 to 4.7 pg/ml. This was probably due to the central hypervolemia induced by immersion. Our results support the hypothesis that central hypervolemia rather than hypotonicity is the primary stimulus for AVP suppression during water immersion in dehydrated subjects. During the early immersion period hypoosmolality might contribute to the AVP suppression. |
| Databáze: | OpenAIRE |
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