This describes an assay for characterization of living pancreas slices, where slices were incubated with a membrane permeant calcium indicator and pericytes/smooth muscle cells were visualized with a fluorescent antibody against the mural cell marker NG2 proteoglycan. Confocal microscopy can be used to simultaneously record changes in the diameter of lectin-labeled blood vessels and cytosolic calcium levels in mural cells in islets. Several stimuli with vasoactive properties can be tested, such as norepinephrine, endothelin-1 and adenosine, to compare human vascular responses with those previously published for mouse islet blood vessels. Data from the assay are published in the indicated defining manuscript.