❙ Arnold Honig † ❙
Zur Rolle der arteriellen Chemorezeptoren bei der Umstellung und der Regulation des Salz- Wasserhaushalt in akuter Höhenhypoxie On the role of arterial chemoreceptors in the adjustment and the regulation of salt water balance in acute altitude hypoxia
Prof. Dr. Arnold Honig † ist am 3.6.2016 verstorben. Es war ihm ein besonderes Anliegen, diesen Beitrag im Jahrbuch zu veröffentlichen. Das Redaktionsteam dankt Herrn Dr. Bert Flemming für die Unterstützung zur Fertigstellung dieses Beitrags. SUMMARY The acute adjustment to well-tolerated high-altitude hypoxia is brought about by initial hemoconcentration as indicated by increases in hematocrit and plasma protein concentration. This rapid hemoconcentration can only be related to a decrease in body water that relies on both reduced water intake and increased water excretion. Given the constancy of the osmolality of body fluids, this must be accompanied by a decrease in NaCl intake and/or increased NaCl excretion. In fact, studies in healthy young subjects report on a so-called altitude natriuresis and diuresis. From several studies in humans as well as various animal species it is conclu ded, that the reflexes that bring about the decrease in NaCl intake and increase in NaCl excretion are triggered by arterial chemoreceptors located in the aorta and the carotid arteries. In addition, the chemoreceptors actuate respiratory and cardiovascular changes via neuronal and humoral pathways. The responses to stimulation of the chemoreceptors are modulated or may even be abolished by conditions such as old age and various diseases including hypertension. The physiological acute adaptation to high-altitude hypoxia can by supported 47
