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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of prolonged in vivo heparin treatment upon vasomotor responses and content of cholesterol and energy related compounds were studied in isolated thoracic and abdominal aortas from Watanabe heritable hyperlipidemic (WHHL) rabbits. Unfractionated heparin was administered subcutaneously (2 mg/kg twice a day) to 3-month-old WHHL rabbits for a period of 6 months. A group of WHHL rabbits was treated with saline solution and considered as control. Aortic cholesterol infiltration and serum cholesterol were not significantly decreased by the prolonged heparin treatment. In heparin-treated WHHL rabbits, the in vitro aortic endothelium-dependent relaxation produced by acetylcholine or calcimycin (A 23187) was greater than in saline-treated WHHL group. ATP-induced aorta relaxation (endothelium-dependent and endothelium-independent) did not vary significantly in the two groups of WHHL rabbits, even after mechanical removal of endothelium. Also the noradrenaline-induced aorta contraction did not vary between the two groups of WHHL rabbits. No significant variation in energy-related compounds (except for ADP) was found in the aortic arch. These results suggest that heparin produces a protective effect on aortic tissue by acting mainly at endothelial level.
Atherosclerosis 1992 Jan
PMID:Protective role of heparin on in vitro functional aortic response in Watanabe heritable hyperlipidemic rabbits. 157 18

We have examined the action of endothelin on healthy and diseased human epicardial coronary arteries to assess its possible role in coronary vascular disorders such as vasospasm and atherosclerosis. Endothelin (10(-10) mol l-1-10(-7) mol l-1) produced dose-dependent contractions in both normal and diseased vessels. The level of constriction was significantly greatly in healthy vessels at 10(-8) mol l-1 endothelin. A greater response was recorded in smaller, more distal vessel segments, irrespective of the pathology of the tissue. Endothelium denudation of disease-free segments had no significant effect on the response to endothelin. In the presence of a threshold dose of endothelin (10(-9) mol l-1), there was no measurable increase in the tension generated by potassium chloride, the thromboxane-mimetic U46619, noradrenaline and histamine. However, the response to 5-HT showed a large increase in arteries from four patients (440-147%) but slight or no increase in arteries from another three patients. We conclude that the interaction with other vasoconstrictor substances is a possible mechanism whereby endothelin may be involved in coronary artery vasospasm. In addition, endothelin may also be involved in the regulation of vascular tone of the small vessels of the heart.
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PMID:Effect of endothelin on normal and diseased human coronary arteries. 158 46

The purpose of the present study was to investigate the effects of hypercholesterolemia on sympathetic vascular responsiveness in the perfused rabbit carotid artery. Two groups of rabbit carotid arteries were evaluated for the simultaneous measurement of noradrenaline (NA) release and vasoconstrictor response induced by electric nerve stimulation and for exogenous NA-induced vasoconstriction in vitro. One group of rabbits was fed a diet containing 0.5% cholesterol for 2 weeks and the other group was fed standard rabbit chow. By scanning electron microscopy, monocytes adhering to the endothelial cells and penetrating into the subendothelium were observed. Neither endothelial denudation nor platelet adhesion could be detected. Rabbit carotid arteries were cannulated and perfused with a physiological solution at a constant flow rate. The vessels were subjected to both transmural field stimulation (TFS; 1.5-24 Hz) and exogenous NA administration. TFS caused a frequency-dependent increase in endogenous NA release with subsequent pressor responses in both groups. Exogenous NA also induced a dose-dependent pressor response, but a significant reduction was observed in the cholesterol-fed group. Methoxamine induced a similar response in both groups. It was concluded that hypercholesterolemia decreased the sensitivity of extrajunctional alpha-receptors in the perfused rabbit carotid artery.
Atherosclerosis 1992 Jun
PMID:Vascular contraction in perfused carotid arteries of cholesterol-fed rabbits. 163 74

Adrenaline, noradrenaline and dopamine excretion was investigated in essential hypertension (n = 20), atherosclerotic heart failure (n = 20, NYHA class II and III), chronic angina (n = 10) and in healthy controls, in four time intervals: between 600-1200, 1200-1800, 1800-2400, 2400-600. Fluorimetric method of Anton and Sayre was employed. In patients with essential hypertension the circadian rhythm of adrenaline, noradrenaline and dopamine excretion was maintained but in all time intervals excretion of dopamine was decreased. In individuals with congestive heart failure due to atherosclerosis and in patients with ischemic heart disease, physiological circadian rhythm of adrenaline and noradrenaline excretion was found to be abolished. This was not the case with dopamine excretion which was undisturbed.
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PMID:[Hypertension, heart failure and angina pectoris. Diurnal rhythm of urinary excretion of catecholamines]. 164 Jun 65

Characterization of P2-purinoceptor subtypes has facilitated understanding of the many diverse effects produced by purine nucleotides. P2X-Purinoceptors are located on vascular smooth muscle where they mediate vasoconstriction resulting from ATP released as a cotransmitter with noradrenaline from sympathetic nerves. P2Y-Purinoceptors are usually located on the vascular endothelium where they have a role as mediators of vascular relaxation by locally produced ATP. In some vessels, P2Y-purinoceptors are also located on the smooth muscle, perhaps in association with purinergic or sensory nerves, where they can elicit direct relaxation to neuronally released ATP. The net effect of ATP and its analogues on isolated vessels or on vascular beds will be the results of actions mediated by P2X- and P2Y-purinoceptor subtypes, although changes in vascular tone and in integrity of nerves and endothelial cells may alter the balance of the response. Such changes have been observed in diseased states (e.g., atherosclerosis) and may have important implications for the involvement of P2-purinoceptors in, for example, vasospasm. The development of selective and potent antagonists to P2X- and P2Y-purinoceptors has so far remained elusive, and their therapeutic potential can only be guessed.
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PMID:Roles of P2-purinoceptors in the cardiovascular system. 164 96

Serum and aortic tissue cholesterol levels in parallel with aortic relaxation to endothelium-dependent and independent drugs were determined in Watanabe heritable hyperlipidemic (WHHL) rabbits in comparison with New Zealand (N.Z.) normocholesterolemic rabbits, aged 4-14 months. Serum cholesterol was elevated (626 +/- 99 mg/100 ml) in 4-6-month-old WHHL rabbits and significantly lower in 12-14-month-old animals (344 +/- 51 mg/100 ml). Cholesterol infiltration in thoracic aorta was high in young WHHL compared with N.Z. rabbits (0.88 +/- 0.3 mg/100 mg fresh tissue vs. 0.08 +/- 0.003 mg/100 mg, respectively) and it did not vary with age. In N.Z. rabbits, serum and aortic cholesterol levels were low from 4 to 14 months of age. The aortic relaxation to acetylcholine (0.03-3 microM) on EC50 noradrenaline precontracted rings was similar in 4-6-month-old WHHL and N.Z. rabbits of the same age. In WHHL rabbits, the relaxation to acetylcholine was significantly reduced in 7-11- (-35% at maximum) and in 12-14-month-old rabbits (-40% at maximum). In N.Z. rabbits the response to acetylcholine was not modified in the 3 age groups. The relaxation to ATP (30 microM to 3 mM) was reduced by age both in N.Z. and in WHHL rabbits, but in 12-14-month-old WHHL rabbits the maximal relaxing response was significantly more elevated than in age-matched N.Z. rabbits (50.1 +/- 2.5% vs. 35.1 +/- 3.2%, respectively). The aortic relaxation to NaNO2 (10 microM to 3 mM) was reduced by age both in N.Z. and in WHHL rabbits.(ABSTRACT TRUNCATED AT 250 WORDS)
Atherosclerosis 1991 Aug
PMID:Aortic response to relaxing agents in Watanabe heritable hyperlipidemic (WHHL) rabbits of different age. 179 50

New Zealand White rabbits fed a low-level cholesterol-enriched diet (0.1%) were used to study and characterize a possible model of experimental atherogenesis. For the determination of the degree of atherosclerosis, more consistent and reproducible morphometric methods were used. Simultaneously the influence of plasma cholesterol levels on vascular noradrenaline content was studied. The effect of a new lipid-regulating drug (0.1% L 44-0, the N-oxide of a nicotinic acid derivative) on analyzed parameters was studied as well. This study suggests that the low-level cholesterol-enriched diet is atherogenic, with macroscopically detectable lesions of atherosclerosis becoming apparent by week 12 of the study. The same diet increases the vascular noradrenaline content in the renal artery and in the femoral artery and vein; however, it does not influence that content in the carotid and mesenteric arteries. L 44-0 counteracts most of the observed effects.
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PMID:Experimental atherogenesis and vascular noradrenaline content in NZW rabbits and activity of a new nicotinic acid derivative (L 44-0). 179 52

The authors studied the effect of various calcium antagonists--verapamil (VP) and Mg2+ (MgCl2) on the character of affection of the vascular wall ulcer conditions of prolonged hypercholesterolemia (HCE). The blood cholesterol (CS) content increased by the end of the 8th month of HCE to eight-fold the value in intact animals. The specific atherosclerotic changes in this case occupied approximately 80% of the area of the thoracic aorta whose functional properties changed essentially. The values of constricting responses of bands to noradrenaline (NA) was 45% of that in intact rabbits, the dilatating responses to acetyl choline (AC) and nitroglycerin (NG) were 20% and 35% of those in intact animals, respectively. Combination of HCE with daily VP injection (1 mg) led to a decrease in the area of affection of the aorta by 20%, which hardly affected the severity of HCE. A slightly more pronounced than in animals only with HCE (controls) was the response of bands to NA, AC, and NG (by 5, 30, and 15%, respectively). The protective effect of MgCl2 (200 mg/kg) was more significant--the affected area of the thoracic aorta reduced by 50% as compared to the controls, the constricting response to NA was maintained at a level exceeding the control level by 25%, the dilatating responses to NG and AC exceeded the control values 2 and 1.5 times, respectively, on the average. The severity of HCE diminished by 50%. The results of the study indicate that the organic and, in particular, the inorganic blocking agents of the calcium canals possess a marked angioprotective action and may be applied for the prevention of vascular atherosclerosis.
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PMID:[Efficacy of vascular wall protection from atherosclerotic damage using various calcium antagonists]. 205 37

In the present study we used a new model, in which the positioning of a non-occlusive collar around the rabbit carotid artery results, within 7 days, in the generation of a neo-intima, a precursor lesion of atherosclerosis. We investigated the effects of this intimal proliferation on the responsiveness to serotonin (5-hydroxytryptamine, 5-HT) and noradrenaline (NOR) after 1, 2 and 7 days. Already after 1 day the collar-treated arteries were more sensitive to 5-HT, but not to NOR. This sensitivity persisted over a period of 7 days. However, the development of a neo-intima diminished the maximum contractile force to NOR after 2 and 7 days, but not to 5-HT. These results demonstrate that there is a relatively selective increase in sensitivity to 5-HT during neo-intima formation, even without hyper-cholesterolaemia.
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PMID:The effect of a developing neo-intima on serotonergic and adrenergic contractions. 207 25

Serotonin is a widely distributed amine, although 95% is found in the enterochromaffin cells of the gastrointestinal mucosa. Its effects are mediated via a large number of receptors differing in their physiological and pharmacological properties. Its principal actions are on the cardiovascular system, both directly and potentiating the effects of the vasoconstriction from noradrenaline, angiotensin and histamine; similarly it potentiates the effect of various platelet aggregating substances. There is evidence that 5-hydroxytryptamine releases endothelium-derived relaxing factor attenuating its direct constriction effect and in the human forearm an increase in flow is seen from serotonin. In the absence of endothelium as in atherosclerosis, vasoconstriction occurs. Serotonin antagonism may have useful therapeutic effects and ketanserin has undergone wide evaluation. There is evidence that ketanserin should be avoided with potassium-losing diuretics as an increased mortality has been reported with the combination.
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PMID:Serotonin: receptors and antagonists--summary of symposium. 213 73


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