Sympathetic nervous and hemodynamic responses to lower body negative pressure in hyperbaria in men
| Autor: | Keizo Shiraki, Sueko Sagawa, Yutaka Endo, Katsuya Yamauchi, Yuka Tsutsui, Fumio Yamazaki |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Adult
Male Sympathetic nervous system Sympathetic Nervous System Physiology Hypovolemia Hemodynamics Blood Pressure Pressoreceptors Blood volume Norepinephrine Heart Rate Stress Physiological Physiology (medical) Heart rate medicine Humans Muscle Skeletal Stroke Lower Body Negative Pressure business.industry Stroke Volume medicine.disease Electrophysiology Autonomic nervous system Atmospheric Pressure medicine.anatomical_structure Regional Blood Flow Anesthesia medicine.symptom business |
| Zdroj: | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 282:R38-R45 |
| ISSN: | 1522-1490 0363-6119 |
| DOI: | 10.1152/ajpregu.2002.282.1.r38 |
| Popis: | The present study was designed to test the hypothesis that sympathetic nerve activity is attenuated in a hyperbaric environment. Response of muscle sympathetic nerve activity (MSNA) to central circulatory hypovolemic stress, lower body negative pressure (LBNP), was measured in nine men at normal and at 3 atm pressures. The stress consisted of 4 min each of control and LBNP at −20 and −40 mmHg. In addition to MSNA, heart rate, stroke volume (SV), forearm blood flow (FBF), and volume of the lower leg were recorded. A reduction of baseline HR occurred with increased forearm vascular resistance at 3 atm abs. The baseline MSNA decreased during hyperbaria. MSNA increased progressively with increasing LBNP in both atmospheric pressures, and the change from the baseline (ΔMSNA) was similar in both conditions. Changes in SV, FBF, and volume of the lower legs in response to LBNP were not statistically different during exposure to 2 atm pressures. The present study suggests that hyperbaria attenuates sympathetic nerve activity; however, its responsiveness to hypovolemic stress was not affected by hyperbaric exposure. |
| Databáze: | OpenAIRE |
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