Validation of indirect systolic blood pressure measurement in ether anaesthetised rats

Systolic blood pressures and plasma catecholamine concentrations were determined in conscious and ether-anaesthetised male spontaneously hypertensive (SHR), Wistar-Kyoto normotensive (WKY/N), Wistar (W) and Sprague-Dawley (SD) rats. When compared to conscious animals, plasma noradrenaline concentrations were significantly higher in all four strains of ether-anaesthetised rats. Only the SHR rats did not show an elevation in plasma adrenaline concentration when anaesthetised with ether. A good correlation was obtained between systolic blood pressures measured indirectly, using a tail-cuff method with two different sensors, in ether-anaesthetised rats and pressures measured directly, via an indwelling carotid catheter, in conscious unrestrained animals. It is concluded that, while ether anaesthesia elevates plasma catecholamine concentrations in rats, the increase in plasma catecholamines has little, if any, effect on indirect systolic blood pressure measurements.