Imaging remodeling of the actin cytoskeleton in vascular smooth muscle cells after mechanosensitive arteriolar constriction

Abstract

Experiments were performed to determine whether remodeling of the actin cytoskeleton contributes to arteriolar constriction. Mouse tail arterioles were mounted on cannulae in a myograph and superfused with buffer solution. The α1-adrenergic agonist phenylephrine (0.1-1 μmol/1) caused constriction that was unaffected by cytochalasin D (300 nmol/1) or latrunculin A (100 nmol/1), inhibitors of actin polymerization. In contrast, each compound abolished the mechanosensitive constriction (myogenic response) evoked by elevation in transmural pressure (PTM; 10-60 or 90 mmHg). Arterioles were fixed, permeabilized, and stained with Alexa-568 phalloidin and Alexa-488 DNAse I to visualize F-actin and G-..