title: [Long-term antiorthostasis (-90 degrees) of animals as a model of critical disorders of homeostasis].
abstract: The cardiovascular effect of head-down tilt (at an angle of -90 degrees) was investigated in 25 mongrel dogs exposed to general anesthesia, myorelaxation or pulmonary ventilation. Changes in the circulation and contractility parameters can be subdivided into three periods. At early stages of the exposure an increase in contractile function and hemodynamic changes typical of preload were seen. At later stages progressive disorders of systemic and regional hemodynamics, inhibition of contractile function, and increasing metabolic changes were observed. All this resulted in the death of the animals after 12-20 hours of head-down tilt. Gross structural changes that occasionally were irreversible were detected in organs of the dead animals.
mesh_terms: D000136:Acid-Base Equilibrium; D000818:Animals; D001794:Blood Pressure; D001831:Body Temperature; D002302:Cardiac Output; D004285:Dogs; D005260:Female; D006439:Hemodynamics; D006706:Homeostasis; D008297:Male; D008954:Models, Biological; D009069:Movement Disorders / Q000503:physiopathology*; D009200:Myocardial Contraction; D011187:Posture; D013997:Time Factors; D014655:Vascular Resistance
vernacular_title: Prolongirovannyĭ antiortostaz (-90 gradusov) zhivotnykh kak model' kriticheskikh narusheniĭ gomeostaza.