Increase and regression of the protective effect of high altitude acclimatization on the isoprenaline-induced necrotic lesions in the rat myocardium.
Cardiac resistance to the cardiotoxic effect of isoprenaline--ISO (single dose of 0.1 mg X kg-1) was studied in rats acclimatized to intermittent high altitude--IHA (barochamber, 8 h a day, 5 days a week, stepwise up to 7000 m). The extent of lesions was evaluated quantitatively by means of the increased accumulation of 203HgCl2. Five weeks' acclimatization was followed by a marked increase in the resistance of the myocardium to the necrogenic effect of ISO; this effect was more expressed in the left ventricle, so that the right to left difference generally observed under normoxic conditions disappeared. The increased resistance of the myocardium to ISO-induced damage persisted long after the animals had been returned to normoxic conditions; even six weeks after the last hypoxic exposure the sensitivity of the myocardium to damage had still not returned to the values of unacclimatized animals.
D000064:Acclimatization; D000273:Adipose Tissue / Q000473:pathology; D000531:Altitude; D000818:Animals; D001835:Body Weight; D004351:Drug Resistance; D004435:Eating; D006321:Heart / Q000187:drug effects; D000860:Hypoxia / Q000473:pathology; D007545:Isoproterenol / Q000506:poisoning*; D008297:Male; D009206:Myocardium / Q000473:pathology*; D009336:Necrosis; D009929:Organ Size; D051381:Rats; D011919:Rats, Inbred Strains
D007545:Isoproterenol