Postnatal development from day 21 to 50 in C57BL/6 mice was associated with an increase in heart rate (396 to 551 beats/min) and mean arterial blood pressure (86 to 110 mmHg).
Knowledge of the developmental changes of cardiovascular parameters in the genetic background of a mouse strain is important for understanding phenotypic changes in transgenic or knockout mouse models for heart disease. We studied arterial blood pressure and myocardial contractility in mice of the common background strain C57BL/6, aged 21 days postnatal day 21 (P21) to 580 days. Heart rate increased during maturation from 396 beats/min at P21 to 551 beats/min at postnatal day 50 (P50), and mean arterial blood pressure increased in parallel from 86 to 110 mmHg and remained constant afterward. Echocardiographically determined left ventricular myocardial wall dimensions (R = 0.79, P or =6 Hz. P21 myocytes developed positive staircases at 8 and 10 Hz, and adult myocytes also developed them at 6 Hz. Blood pressure increase during maturation until P50 may originate from increasing single cardiomyocyte contractility.
Tiemann et al. (Sat,) reported a other. Postnatal development vs. Postnatal day 21 was evaluated on Arterial blood pressure and myocardial contractility. Postnatal development from day 21 to 50 in C57BL/6 mice was associated with an increase in heart rate (396 to 551 beats/min) and mean arterial blood pressure (86 to 110 mmHg).