Electrical coupling between smooth muscle and endothelium in arterioles ofthe guinea-pig small intestine

Equations describing the steady-state passive electrical properties of arte rioles have been derived. The arteriole was modelled as having two thin lay ers of cells (muscle and endothelium) with strong electrical coupling betwe en cells within a layer and variable coupling between the layers. The model indicated that spread of membrane potential changes was highly dependent o n the thickness of cells within the layers. The model was also used to iden tify the optimal experimental strategy for detecting coupling between the t wo layers, and experiments were carried out on arterioles from the guinea-p ig small intestine. Thickness of the endothelial layer was measured using e lectron microscopy and was found to be around 0.5 mum. Electrical input res istance was measured in intact arterioles and compared to input resistance of arterioles from which the endothelium had been removed. The experiments confirmed that there was a strong electrical coupling between the muscle an d endothelium in these vessels.