Measurement of Blood Pressure Blood pressure represents an integrated measure of overall cardiovascular function, and is affected by stroke volume, heart rate, inotropic state, and vascular tone. Abnormalities of blood pressure regulation (primarily hypertension, but also hypotension) are associated with major cardiovascular morbidity and mortality, and are epidemiologically associated with diabetes. Three complementary technologies are available within the core for the measurement of BP: 1) non-invasive tail-cuff plethysmography, 2) direct arterial measurement by intracarotid catheterization, and 3) telemetry via implanted catheter. Tail-cuff Plethysmography. Plethysmography (tail-cuff) is performed using a tail-cuff BP apparatus (BP-2000, Visitech Systems, Inc.). This technology is non-invasive and there is good concordance with the direct BP measurements described below. Carotid Catheterization. Direct arterial measurements are obtained via a chronically placed catheter in the carotid artery. The catheter is connected to a TXD-310 transducer and BP measured using a Digi-Med BPA 400 (Micromed). Experiments using this approach are typically coordinated with metabolic measurements. Carotid and Jugular Vein Catheterization. The dual catheter approach (arterial and venous) allows for BP measurements in response to specific pharmacological infusions in the awake or anesthetized state; and enables evaluation of both peripheral and central mechanisms of BP regulation. Telemetry. Telemetered direct BP measurement is performed using an implanted micro-miniature device (PA-C10, DSI) implanted subcutaneously with the catheter typically placed in the right carotid artery. The mouse is housed individually in a cage placed over the receiver platform and BP data digitally recorded via the DATAquest A.R.T. system (DSI). Advantages of this approach include the ability to continuously record BP over a period of weeks, to assess the diurnal range in BP, and stress artifact induced by animal handling is avoided.