mortality/aging
• mice exhibit increased mortality after 16 weeks of age
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cardiovascular system
• ventricular effective refractory period is prolonged
• however, mice do not exhibit conduction abnormalities, with normal sinus rhythm activation patterns and conduction velocities in pacing experiments
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• QRS amplitude is decreased
• however, hemodynamic parameters, including left ventricular end-diastolic pressure, +dP/dt, -dP/dt, and the relaxation constant Tau are unchanged, indicating unchanged ventricular function
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• action potential duration in cardiac myocytes under current-clamp conditions are prolonged and isoproterenol leads to action potential prolongation with some myocytes developing early afterdepolarizations
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• ventricular myocytes exhibit smaller current density at 0 mV and dinitrophenol, pinacidil or bimakalim fail to activate sarcolemmal ATP-sensitive K+ channels in cardiac myocytes indicating that mice lack sarcolemmal ATP-sensitive K+ channels
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