Multiple calcium signaling pathways in Mardin-Darby canine kidney cells.
Effects of various receptor agonists on cytoplasmic Ca2+ concentration ([Ca2+]i) were examined in fura-2-loaded Mardin-Darby canine kidney (MDCK) monolayer cells. Carbachol (100 microM) increased [Ca2+]i which slightly declined to a sustained increase in [Ca2+]i. On the other hand, [Ca2+]i elevated by 100 nM bradykinin (BK) declined to a resting level of [Ca2+]i even in the presence of BK. After washout of BK, the subsequent addition of a higher concentration of BK (1 microM) caused a smaller increase in [Ca2+]i than that induced by 100 nM BK. Isoproterenol (100 microM) did not increase [Ca2+]i by itself but caused an transient increase in [Ca2+]i in the presence of 1 mM isobutyl-methylxanthine (IBMX). Prostaglandin E1 (1 microM) resulted in a slight increase in [Ca2+]i which was potentiatedin the presence of 1 mM IBMX. The microsomal Ca(2+)-ATPase inhibitor thapsigargin (100 nM) caused a sustained increase in [Ca2+]i. These results suggest that MDCK cells have multiple Ca2+ signaling pathways which may regulate epithelial cell functions.
Sakano
S
S
Department of Pharmacology, School of Medicine, Sapporo Medical University, Japan.
Takemura
H
H
Ohshika
H
H
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002217:Carbachol / Q000494:pharmacology; D002460:Cell Line; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D004285:Dogs; D004848:Epithelium / Q000378:metabolism; D016257:Fura-2 / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D007668:Kidney / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D010738:Type C Phospholipases / Q000378:metabolism
D015544:Inositol 1,4,5-Trisphosphate; D002217:Carbachol; D000242:Cyclic AMP; D010738:Type C Phospholipases; D000262:Adenylyl Cyclases; D000252:Calcium-Transporting ATPases; D001920:Bradykinin; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine; D016257:Fura-2