Orthostatic hypotension: with particular reference to experimentally-induced orthostatic hypotension in dogs.

Blood pressure (BP) and heart rate (HR) were measured while standing in a stable position for SPF beagle dogs consisting of 4 females with an average weight of 8.73 +/- 0.58 kg and average age of 7.38 +/- 0.12 months. No anesthetic was used during the procedure. These dogs were subjected to a postural change, a 90 degrees-tilt standing position, and BP and HR were measured one minute and ten minutes later. In addition, 20 mg/kg of tetraethyl-ammonium bromide (TEA) as a gangliolytic drug was administered by i.v. injection within 30 seconds, and then BP and HR were measured in the resting state for 20 minutes. When changing from the resting position to the 90 degrees-tilt standing position after administration of TEA, these were significant decreases in systolic BP, diastolic BP and mean arterial BP one minute and ten minutes later. An experimental model of orthostatic hypotension was considered to have been achieved during these methods.