Effects of vasoactive mediators on the rat lung pericyte: Quantitative analysis of contraction on collagen lattice matrices

Pericytes are contractile cells of the microvasculature which may contribut e to the hypotension and increase in permeability that are present during i nflammation and late-stage sepsis. The purpose of this study was to examine the contractile effects, if any, of septic modulators on the lung pericyte . Contractile effects were qualitatively examined using a previously develo ped silicone rubber method. This study further demonstrates a quantitative method for measuring the contraction of lung pericytes cultured on a collag en lattice. Contraction was measured by the change in collagen matrix area in response to vasoactive stimuli. Bradykinin and serotonin significantly i ncreased contraction in a dose-dependent manner, with a maximum increase in contraction twice that of control. Forskolin and adenosine caused relaxati on, also in a significant dose-dependent manner, with a maximum decrease in contraction of 80 and 30-40%, respectively. Histamine had no effect on con tractility in either the silicone rubber or the collagen lattice assay. The se results show that the lung pericyte, like the retinal pericyte, is a con tractile cell and can be stimulated to contract or relax in vitro by the pr esence of certain inotropic agents present during inflammation and sepsis. These responses may play a role in microvascular regulation. (C) 1999 Acade mic Press.