Abstract
Functional and metabolic parameters of thoracic aorta from Watanabe heritable hyperlipemic (WHHL) rabbits (aged 11–14 months) were investigated in vitro. The aortic preparations, normally responsive to noradrenaline, showed a diminished response to the endothelium-dependent agent, acetylcholine, in comparison with control preparations from age-matched New Zealand rabbits (maximal relaxation: 33 ± 4% in WHHL vs. 52 ± 2% in controls; P < 0.005). ATP relaxant effect (only partially endotheliumdependent) was unimpaired in WHHL aorta, and it was much higher than in controls (maximal response: 63 ± 6% vs. 37 ± 3%, respectively; P < 0.005). The response to NaNO 2, an endothelium-independent relaxant, was unchanged in WHHL aortas. Acetylcholine-induced response was found to be inversely related to the degree of total cholesterol infiltration in aorta ( r = −0.62, P < 0.05). No correlation was observed between either total serum cholesterol or triglycerides and ACh-induced response. Furthermore, the concentration of adenine nucleotides and nucleosides in the aortic tissue of WHHL rabbits was lower than in controls, indicating a loss of energy balance. The results indicate a functional damage induced by genetic hyperlipidemia on endothelium-dependent relaxation and an impairment of energy-rich phosphate metabolism of the aortic wall. The relationship between functional and metabolic parameters is not yet clarified.
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