View article

Alterations of cardiac contractility caused by thiamine deficiency were studied on three groups of 2 month old male Wistar rats: B₁, fed a thiamine deficient diet, PF pair fed, which received an amount of thiamine free diet determined on the daily consumption of B₁ animals, supplemented with appropriate thiamine supply, C ad libitum fed controls. The animals were studied after 35 days of dietary treatment. Force-velocity curves were determined in right ventricle papillary muscles. Shortening velocity was significantly lower in B₁ and PF than in C muscles and in B₁ than in PF muscles. The ability to develop tension was not altered. Myosin ATPase activity was assayed in preparations of myofibrils and in preparations of purified myosin. Both CaMg activated myofibrillar ATPase activity and Ca-activated myosin ATPase activity were significantly reduced in B₁ and PF compared to C myocardium. Furthermore Ca …