This Article Full Text Full Text (PDF) All Versions of this Article: 146/11/4844    most recent Author Manuscript (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Yi, F.-X. Articles by Bird, I. M. Search for Related Content PubMed PubMed Citation Articles by Yi, F.-X. Articles by Bird, I. M.

Pregnancy-Specific Modulatory Role of Mitochondria on Adenosine 5'-Triphosphate-Induced Cytosolic [Ca²⁺] Signaling in Uterine Artery Endothelial Cells

Perinatal Research Laboratories, Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, Wisconsin 53715

Address all correspondence and requests for reprints to: Fu-Xian Yi, M.D., Ph.D., University of Wisconsin-Madison, Department of Obstetrics and Gynecology, Perinatal Research Laboratories, 7E Meriter Hospital/Park, 202 South Park Street, Madison, Wisconsin 53715. E-mail: fuxianyi{at}wisc.edu.

Vascular endothelial cells respond to extracellular ATP by inositol 1,4,5-trisphosphate-mediated Ca²⁺ release from the endoplasmic reticulum followed by Ca²⁺ influx and subsequent synthesis of vasodilators. In this study, the contribution of mitochondria in shaping the ATP-induced Ca²⁺ increase was examined in ovine uterine artery endothelial cells from nonpregnant and pregnant (late gestation) ewes (NP- and P-UAEC, passage 4). The mitochondrial protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) induced a rapid mitochondrial depolarization. CCCP also slowly increased cytosolic [Ca²⁺] ([Ca²⁺]_c), which then gradually declined to 10–20 nM above resting level. Pretreatment with CCCP for 30 min significantly inhibited both ATP and thapsigargin-induced [Ca²⁺]_c, with inhibition in NP-UAEC more effective than in P-UAEC. Pretreatment of mitochondrial permeability transition pore inhibitor cyclosporine A did not affect CCCP-induced mitochondrial depolarization, but delayed CCCP-induced [Ca²⁺]_c for about 12–15 min (we termed this the "window of time"). During the cyclosporine A-delayed window of time of CCCP-induced [Ca²⁺]_c, ATP induced a normal Ca²⁺ response, but after this window of time, ATP-induced [Ca²⁺]_c was significantly inhibited. Pretreatment of oligomycin B to prevent intracellular ATP depletion by F0F1-ATPase did not reduce the inhibition of ATP-induced [Ca²⁺]_c by CCCP. Ruthenium red, a mitochondrial Ca²⁺ uptake blocker, did not mimic the inhibition of Ca²⁺ signaling by CCCP. In conclusion, our data show that mitochondrial Ca²⁺ depletion after dissipation of mitochondrial membrane potential with CCCP inhibits ATP-induced [Ca²⁺]_c, mediated at the level of Ca²⁺ release from the endoplasmic reticulum. Moreover, our data revealed that P-UAEC is more resistant to the inhibitory effect of CCCP on [Ca²⁺]_c than NP-UAEC.