Relationship between Ca2+ sparklets and sarcoplasmic reticulum Ca2+ load and release in rat cerebral arterial smooth muscle.
Enviado por Manuel F Navedo el
Título | Relationship between Ca2+ sparklets and sarcoplasmic reticulum Ca2+ load and release in rat cerebral arterial smooth muscle. |
Publication Type | Journal Article |
Year of Publication | 2011 |
Autores | Takeda, Y, Nystoriak, MA, Nieves-Cintrón, M, Santana, LF, Navedo, MF |
Journal | Am J Physiol Heart Circ Physiol |
Volume | 301 |
Issue | 6 |
Pagination | H2285-94 |
Date Published | 2011 Dec |
ISSN | 1522-1539 |
Palabras clave | Animals, Calcium, Calcium Channels, L-Type, Calcium Signaling, Cerebral Arteries, Luminescent Proteins, Microscopy, Confocal, Microscopy, Fluorescence, Muscle, Smooth, Vascular, Myocytes, Smooth Muscle, Protein Sorting Signals, Rats, Rats, Sprague-Dawley, Recombinant Fusion Proteins, Ryanodine Receptor Calcium Release Channel, Sarcolemma, Sarcoplasmic Reticulum, Sarcoplasmic Reticulum Calcium-Transporting ATPases, Time Factors, Transfection |
Abstract | Ca(+) sparklets are subcellular Ca(2+) signals produced by the opening of sarcolemmal L-type Ca(2+) channels. Ca(2+) sparklet activity varies within the sarcolemma of arterial myocytes. In this study, we examined the relationship between Ca(2+) sparklet activity and sarcoplasmic reticulum (SR) Ca(2+) accumulation and release in cerebral arterial myocytes. Our data indicate that the SR is a vast organelle with multiple regions near the sarcolemma of these cells. Ca(2+) sparklet sites were located at or <0.2 μm from SR-sarcolemmal junctions. We found that while Ca(2+) sparklets increase the rate of SR Ca(2+) refilling in arterial myocytes, their activity did not induce regional variations in SR Ca(2+) content or Ca(2+) spark activity. In arterial myocytes, L-type Ca(2+) channel activity was independent of SR Ca(2+) load. This ruled out a potential feedback mechanism whereby SR Ca(2+) load regulates the activity of these channels. Together, our data suggest a model in which Ca(2+) sparklets contribute Ca(2+) influx into a cytosolic Ca(2+) pool from which sarco(endo)plasmic reticulum Ca(2+)-ATPase pumps Ca(2+) into the SR, indirectly regulating SR function. |
DOI | 10.1152/ajpheart.00488.2011 |
Alternate Journal | Am. J. Physiol. Heart Circ. Physiol. |
PubMed ID | 21984539 |
PubMed Central ID | PMC3233819 |
Grant List | HL-085686 / HL / NHLBI NIH HHS / United States HL-085870 / HL / NHLBI NIH HHS / United States HL-098200 / HL / NHLBI NIH HHS / United States R01 HL098200 / HL / NHLBI NIH HHS / United States T32-HL-07828 / HL / NHLBI NIH HHS / United States |