[Analysis of the vascular reactivity of isolated and blood-perfused rabbit thoracic aortas with support rabbits].

We have developed a new method for perfusing isolated and blood-perfused rabbit thoracic aortae by using conscious support rabbits. The vasoconstrictory and vasodilatory response to vasoactive substances were recorded as the decrease or the increase in intra-chamber pressure of the glass container in which the rabbit thoracic aorta was mounted. Examined were the vascular responses to dl-norepinephrine (NE) and l-isoproterenol (Iso) at different pressure loads to the vessel. NE produced a dose-dependent vasoconstriction which was effectively suppressed by i.v. phentolamine (3 mg/kg). In contrast, Iso produced beta-adrenoceptor-mediated vasodilations in a dose-dependent manner (dl-propranolol, 0.5 mg/kg, i.v.). The present experiments were performed at different pressure loads (pressure changes both in the vessel-mounted chamber and a Starling pneumatic resistance set connected in the way of a series circuit). Our newly developed system for perfusion of isolated vascular vessels with conscious support rabbits has some advantages over the existing methods for analysing vascular reactivity in terms of being perfused with arterial blood, having a simulated peripheral resistance apparatus in the circuit and showing a distinct vasodilatory response to i.a. Iso.