Mechanics of the carotid artery wall and baroreflex sensitivity after acute ethanol administration in young healthy volunteers

Abstract

The effects of ethanol administered orally (300 mg/kg in 250 ml of water) or intravenously (7.5 mg.min(-1).kg(-1) in 250 ml of saline over 40 min) on common carotid haemodynamics, wall mechanics and baroreflex sensitivity were compared with the effects of the intravenous infusion of 250 ml of saline. Ethanol or saline was administered to 10 healthy volunteers after 30 min of supine rest, and measurements were obtained 40 min (median; range 34-46 min) after administration. After ethanol administration, the plasma alcohol level rose from 0 to 0.3+/-0.07 g/l. Mean arterial blood pressure had risen slightly at 20 min, but was normalized by 40 min, the time at which the haemodynamic study was performed. Heart rate decreased after infusion of either saline or alcohol, but was unchanged after oral ethanol administration. Both oral and intravenous ethanol administration were associated with significant decreases in baroreflex sensitivity, carotid shear stress and blood velocity, compared with resting values, while the mean carotid artery diameter was increased, and blood viscosity and mean blood flow were unchanged. No changes were observed in these parameters after saline administration. Ethanol, administered either intravenously or orally, increased the stiffness of the carotid artery and decreased the pulsatility (systo-diastolic changes) of its diameter. A direct, statistically significant correlation was found between the decrease in shear stress and the decrease in baroreflex heart rate control sensitivity after both modes of alcohol administration, while no such correlation was found between the increase in the Peterson elastic modulus and the decrease in carotid diameter pulsatility on the one hand or the decrease in baroreflex sensitivity on the other. In conclusion, reduced shear stress associated with vasodilatation of the carotid artery wall may contribute to the decrease in baroreflex sensitivity observed after acute ethanol administration.

Acute cardiovascular responses elicited by consumption of beer in healthy people

“…The baroreflex did not improve significantly after beer drinking in contrast with the observation noticed after water consumption. Our findings are to some extent in agreement with previous reports showing reduced barorelex sensitivity after alcohol administration [11]. Explanation for the mechanism by which alcohol affects BRS range from direct interference with central regulation of the reflex to local carotid vasodilatation with decreased shear stress at receptor sites [12].…”

Associations of metabolic variables with arterial stiffness in type 2 diabetes mellitus: focus on insulin sensitivity and postprandial triglyceridaemia

“…However, we assessed fasting, postprandial and mean 24‐h triglyceride concentrations, and found that these were not significantly associated with any of the outcome variables in this study. Among healthy subjects, the association between triglyceride concentrations and arterial stiffness is also weak [15,34] or absent [35]. We conclude therefore that an increase in arterial stiffness is an unlikely explanation for the association between hypertriglyceridaemia and cardiovascular risk in type 2 diabetes.…”

Baroreceptor sensitivity and baroreceptor effectiveness index in cirrhosis: the relevance of hepatic venous pressure gradient

“…A BRS attenuation by continuous ethanol exposure or consumption has been shown in both experimental (29) and clinical (30) studies. Furthermore, acute ethanol administration has been described to decrease the BRS (31). However, it should be noted that all our patients had not been taking alcohol for at least 6 months.…”