Reduced sympathetic noradrenergic neurotransmission in the tail artery of Donryu rats fed with high cholesterol‐supplemented diet

Abstract

1 Sympathetic neurotransmission and noradrenaline content of the tail artery of Donryu rats fed for 2 months with a cholesterol-supplemented diet enriched with 4% cholesterol, 1% cholic acid, 0.5% thiouracil (CCT), were examined. 2 Total serum cholesterol level of CCT fed rats (7.05+1.77 mg ml 71 , n=8) was signi®cantly greater than lab-chow fed controls (2.58+0.32 mg ml 71 , n=8). Low density lipoprotein level was also signi®cantly increased in CCT-fed (1.79+0.26 mg ml 71 , n=8) compared with control fed rats (1.35+0.25 mg ml 71 , n=8) but plasma levels of triglyceride and high density lipoproteins did not dier signi®cantly between the two groups. 3 Contractile responses of the arterial rings to transmural nerve stimulation (65 V, 0.1 ms, 4 ± 64 Hz, 1 s), were markedly attenuated in the CCT fed animals compared with the controls. This reduction involved the noradrenergic rather than purinergic component of sympathetic transmission. 4 Vasoconstrictor responses to exogenous noradrenaline (0.01 ± 300 mM) and adenosine 5'-triphosphate (0.3 ± 1000 mM) were unaected by CCT diet, indicating prejunctional alteration of sympathetic neurotransmission during CCT-induced hyperlipidaemia. 5 The noradrenaline content of the tail arteries of CCT fed animals (2.64+0.36 ng mg 71 , n=6) was signi®cantly lower than that of controls (3.82+0.32 ng mg 71 , n=6). 6 These ®ndings show that chronic treatment of Donryu rats with a cholesterol-supplemented diet led to altered levels of circulating lipid fractions accompanied by attenuated sympathetic noradrenergic neurotransmission and reduced noradrenaline content of the rat tail artery.

Fluvastatin Prevents Renal Dysfunction and Vascular NO Deficit in Apolipoprotein E-Deficient Mice

“…2,42,43 In agreement with previous studies, 3,44 we also found that the contractile responses to KCl and phenylephrine were not altered in the aortas and carotid arteries taken from ApoE Ϫ/Ϫ mice. In addition, our data show that chronic fluvastatin treatment significantly enhances the contractile vascular responses to KCl and phenylephrine of carotid and aorta from ApoE Ϫ/Ϫ mice but not from WT mice.…”

“…The consequences of hypercholesterolemia on vascular contractile responses are still controversial, depending on the experimental model used (species, age, diet), 2,40 -42 the vascular preparation, 41,43 and the contracting agent. 2,42,43 In agreement with previous studies, 3,44 we also found that the contractile responses to KCl and phenylephrine were not altered in the aortas and carotid arteries taken from ApoE Ϫ/Ϫ mice.…”

P2 receptors in cardiovascular regulation and disease

“…2 ). Interestingly, fish oil components increase the release of ATP [ 99 ] and a high cholesterol diet decreases ATP release from arteries [ 100 , 101 ].

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P2 receptors in cardiovascular regulation and disease

“…2). Interestingly, fish oil components increase the release of ATP [99] and a high cholesterol diet decreases ATP release from arteries [100,101].…”