Date of Award

5-2001

Degree Type

Thesis

Degree Name

MS Biology

Department

Biology

Advisor

Sulie L. Chang

Committee Member

Ghayasuddin Ahman

Committee Member

Allan Blake

Keywords

Morphine, Permeability, Vascular Endothelial Cell Barriers

Abstract

Using three types of in vitro endothelial cell barrier models, we investigated the direct effects and mechanisms of morphine on vascular permeability. Our current studies illustrate LPS induces permeability across these VEC barriers, and is significantly enhanced when co-treated with morphine, displayed using the [ 14 CJ-inulin paracellular marker. Incubation with morphine alone induces permeability in a concentration­ depeodent manner, and is not blocked by the addition of naloxone. Morphine enhances the detrimental effects of LPS on cell viability and alone also decreases endothelial cell viability, concentration-dependently, which is also not affected by naloxone, as demonstrated by the trypan blue exclusion assay. Using 4',6-diarnidino-2-phenylindole (DAPI) nuclear stain, we reveal LPS- and morphine-induced cell death is through an apoptotic mechanism. Morphine-induced apoptosis is concentration-dependent and not blocked by naloxone once again, and cotreatment with LPS synergizes to induce enhanced apoptosis. Morphine has been shown to induce Fas-mediated apoptosis in immune cells (Yin et al., 1999); however, our VEC models demonstrate a Fas­ independent apoptotic mechanism. Lastly, we confirm that pretreatment of the monolayer with morphine enhances viral penetration, using The Amplicor® Viral RNA Detection Assay. These results suggest that morphine enhances permeability and viral penetration across the vascular endothelium by promoting apoptosis, via a Fas­ independent pathway. This study reveals insight as to how morphine exposure may enhance HIV -1 penetration and further implicate the effects of endotoxins on these physiological barriers.

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