ABSTRACT
Many hypertensive animal models have been developed and used to elucidate the pathophysiology of hypertension and to develop antihypertensive drugs. Among them, the spontaneous hypertensive rat (SHR), deoxycorticosterone acetate (DOCA)-treated and high salt intake rat (DOCA-salt), and high sodium-fed Dahl salt-sensitive rat (HS) models are commonly used. Multiple studies have been conducted, however, elevation in blood pressure in these models due to the reactivity of adrenergic vasoconstriction has not been well characterized in a centralized experiment. In this study, the pressor responses to periarterial nerve stimulation (PNS) or exogenous noradrenaline (NA) infusion were measured in the isolated mesenteric vascular bed with the intestinal tract to investigate the reactivity of mesenteric adrenergic vasoconstriction. The systemic arterial blood pressure of the hypertensive rat models was uniformly elevated compared with their respective controls. However, the changes in perfusion pressure in the mesenteric vascular bed in response to PNS and exogenous NA infusion were quite different depending on the model. The pressor responses to PNS in SHRs and Dahl S HS rats were significantly higher, and those in DOCA-salt rats were significantly lower than those in the controls. The pressor responses to exogenous NA infusion in SHRs were significantly higher, and those in Dahl S HS rats were significantly lower than those in their respective controls. No difference was observed in the pressor responses to the exogenous NA between the DOCA-salt and sham groups. These results demonstrate that the reactivity of adrenergic vasoconstriction is different for each type of experimental hypertensive model rat.