Platelets Do Not Alter Flow-Mediated Dilation or Arterial Conduction in vivo.

The aim of this study was to investigate whether platelets contribute to shear stress and vascular conductance in the iliac vascular bed in vivo. Flow-mediated dilation of pig iliac was induced by downstream injection of acetylcholine (50 μg), and separately, conductance (ΔF/ΔP) was calculated. This was carried out before and after removal of 1 L of arterial blood in 240 mL increments, and each 240 mL was spun in a centrifuge (1,500 rcf for 7 min); platelet-rich plasma was replaced with equal volume of heparinised saline and reinjected.

The vascular glycocalyx is not a mechanosensor in conduit arteries in the anesthetized pig.

Background: The role of the glycocalyx as the endothelial sensor of an increase in blood flow was assessed in the iliac artery in vivo.

Methods: Acetylcholine-induced flow mediated dilation was evaluated before and after vascular glycocalyx disruption. This was accomplished by exposing the iliac lumen to the chemotactic agent fMLP (1 μM; = 6 pigs), concomitant heparinase III (100 mU ml) and hyaluronidase (14 mg ml) ( = 4), and neuraminidase (140 mU ml; = 5), for 20 min in separate iliac artery preparations.

Small and intermediate Ca-sensitive K channels do not play a role in vascular conductance during resting blood flow in the anaesthetised pig.

Flow-induced dilation in resistance arteries is mediated by endothelium-dependent hyperpolarisation via small and intermediate conducting Ca sensitive K channels. The aim of the current study was to assess the effect of blocking both channels, using the toxins apamin and charybdotoxin, on flow-induced dilation in a conduit artery and vascular conductance. Experiments were carried out on the iliac and its vascular bed in anaesthetised pigs (n = 4).

Heparan sulphate and hyaluronic acid components of the glycocalyx do not play a role in flow-mediated dilation of the iliac in the anaesthetized pig.

The shear-stress sensor function of vascular glycocalyx heparan sulphate and hyaluronic acid was investigated in vivo by assessing flow-mediated dilation before and after their removal. Heparinase III exposure (100 mU·mL for 20 min; = 6) did not significantly affect flow-mediated dilation of the iliac, from 0.42 ± 0.