The signaling mechanisms of long distance intercellular calcium waves (far waves) in cultured human uterine myocytes.
Cultured human myocytes exhibit intercellular calcium waves that travel farther than 100 microm ('far waves'). This work investigates the mechanism of far wave propagation. Culture lines were initiated from myometrial biopsies of term pregnant women. Calcium green-1 was used as a fluorescence probe for intracellular free calcium. Serial imaging was performed at a frame rate of 0.83 frames/s. Intercellular calcium waves were mechanically initiated by atraumatically applying small drops of mineral oil onto the surface of the monolayer. Each intercellular calcium wave was scored using a standardized grid, and points were assigned depending upon the distance the wave traveled and the fluorescent intensity observed within each region. Experiments were performed in the presence of inhibitors of gap junctions and connexin hemichannels (octanol), ATP (apyrase and MDL 12330 A), prostaglandins (indomethacin, high concentrations of lanthanum), the prostaglandin transporter, PGT (DIDS), and transmembrane calcium flux (low concentrations of lanthanum). Octanol, apyrase and MDL 12330 A failed to modify the far waves, indicating gap junctions, connexin hemichannels and ATP do not participate in the paracrine mechanism. Indomethacin at 30, 100 and 300 microM, in a dose dependent manner, reduced the far wave score to 0, suggesting a prostaglandin was critically involved in the mechanism. DIDS reduced the far wave score, but did not fully inhibit wave propagation, suggesting the presence of PGT-dependent and -independent components to the mechanism. Lanthanum at 0.1 mM had no effect, but at 1 mM, reduced the far wave score. These results are consistent with PGF2alpha and/or PGE2 being the signal molecule for the PGT-dependent component. Taken together, these data indicate that long distance intercellular calcium waves in cultured human myocytes utilizes a paracrine signaling mechanism, but with more than one extracellular signaling compound.
Young
Roger C
RC
Department of Obstetrics and Gynecology, Medical University of South Carolina, 96 Janathan Lucas Street, Suite 634, Charleston, SC 29425, USA.
Schumann
Ralph
R
Zhang
Peisheng
P
D000255:Adenosine Triphosphate / Q000037:antagonists & inhibitors / Q000378:metabolism; D017920:Antiporters / Q000037:antagonists & inhibitors / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D017630:Connexins / Q000037:antagonists & inhibitors / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D005260:Female; D017629:Gap Junctions / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009215:Myometrium / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D027361:Organic Anion Transporters; D019899:Paracrine Communication / Q000187:drug effects / Q000502:physiology*; D011448:Prostaglandin Antagonists / Q000494:pharmacology; D011453:Prostaglandins / Q000378:metabolism
D017920:Antiporters; D002121:Calcium Channel Blockers; D017630:Connexins; D004268:DNA-Binding Proteins; D027361:Organic Anion Transporters; D011448:Prostaglandin Antagonists; D011453:Prostaglandins; C503526:SLCO2A1 protein, human; D000255:Adenosine Triphosphate; D002118:Calcium