Technique for Cardiovascular Monitoring in Awake Tethered Rats

摘要

We have developed a tethering system for use in awake, freely moving rats that allows for repeated measurement of either cardiac output or direct arterial blood pressure and electrocardiogram (ECG). Cardiac output was measured by the thermodilution technique by using a thermocouple probe and polyethylene tubing surgically implanted in the aortic arch and superior vena cava, respectively. Arterial blood pressure and ECGs were monitored via a carotid arterial catheter and teflon-coated, stainless steel wire electrodes place subcutaneously on the extremities. The catheters, wires, and thermocouple probe were passed subcutaneously to the dorsal cervical area and exteriorized. The animals were then attached to a rodent jacket/spring tether system and allowed to recover for at least 24 to 48 hours before experimental procedures were initiated. In 49 rats, arterial blood pressures and ECGs were analyzed. Similarly, cardiac output was measured in 27 rats.