[Early hypoxic contracture of the myocardium in adult and newborn rats].
The effect of 30 min substrate free hypoxia (H) on isometric tension was studied in isolated myocardium (M) of adult (A) and newborn (N) rats. The perfusion with 50% Na+ H solution caused in AM the development of H contracture which was more than 50% higher than control contracture. H perfusion with 0.1 mM Ca2+, 1.0 mM La3+, and 10.0 mM of caffeine provides the discrimination of control and hypoNa+ contractures. It is assumed that early H contracture in AM is a result of inability of Ca-sequestering system to accumulate intracellular Ca2+ and Ca2+ influxing through the sarcolemma. In myocardium of N rats Na-Ca exchange is proposed as a main source of Ca2+ for H contracture development.
Mashanov
G I
GI
Tsyvían
P B
PB
Arteméva
O G
OG
D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000494:pharmacology*; D015687:Cell Hypoxia / Q000187:drug effects; D003864:Depression, Chemical; D066298:In Vitro Techniques; D007811:Lanthanum / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects*; D051381:Rats; D012964:Sodium / Q000494:pharmacology*; D012996:Solutions; D013268:Stimulation, Chemical
D012996:Solutions; D007811:Lanthanum; D012964:Sodium; D002118:Calcium
Ranniaia gipoksicheskaia kontraktura v miokarde vzroslykh i novorozhdennykh krys.