Vasoactive amine responses in murine cerebrovascular endothelial cells as measured by extracellular acidification rates

Abstract

The Cytosensortrade mark microphysiometer device is capable detecting cellular responses to specific bioactive ligands by measuring the extracellular acidification rate (ECAR). Using microphysiometry, we were able to determine that cerebovascular endothelial cells derived from SJL/J mice were more sensitive to serotonin (maximal ECAR response at 100 nM), whereas BALB/c-derived cerebrovascular endothelial cells (CVE) were relatively insensitive (maximal ECAR response at 30 microM). Serotonin (5HT)(1) and 5HT(2) receptor antagonists inhibited the serotonin-mediated increases in ECAR. The cells' responses to histamine in both strains were similar (maximal ECAR required 100 microM of histamine). H(1) and H(3) receptor subtype antagonists specifically inhibited the histamine responses. Bradykinin also revealed sensitivity differences in that maximal ECAR changes for CVE from SJL/J mice could be observed with 1 microM, as compared to the ECAR responses from BALB/c mice CVE, which required 10 microM. Exposure to bradykinin antagonists revealed that the response was due to the stimulation of B(2) receptors. These microphysiometry results reveal that the cerebrovascular endothelial cells of SJL/J mice tend to be more sensitive to vasoactive substances than those of BALB/c mice.