Nucleotides-induced cytosolic calcium transient and plasma membrane permeability in Chang human liver cells.
Extracellular nucleotides induce changes in cytosolic free Ca++ and also increase plasma membrane permeability to Ca++ ions in Chang human liver cells. Ca++ permeability induced by nucleotides is reversible and inactivated immediately upon removal of agonist. Stimulated cells transferred into the fresh medium and re-exposed to nucleotides demonstrate reopening of Ca++ channel without stimulation of Ca++ transient. Relative potencies of nucleotides to induce membrane permeability and Ca++ transient were: UTP > ATP > gamma-S-ATP > ADP (non-hydrolyzable ATP analogues and AMP had no effect). The permeability is not affected by specific inhibitors of voltage-operated calcium channels (verapamyl,cis-diltiazem and nifedipin). Nucleotides do not produce plasma membrane damages at concentrations up to 1 mM, as shown by exclusion of the propidium iodide. There are at least two types of nucleotides receptors in Chang cell membrane: P2y subtype receptors which is responsible for generation of the Ca++ transient, and P2x subtype receptors which lead to the opening of plasma membrane Ca++ channels upon activation.
Holmuhamedov
E L
EL
Upjohn Laboratories, Kalamazoo, MI 49007, USA.
Bacon
J A
JA
Ulrich
R G
RG
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D002463:Cell Membrane Permeability / Q000187:drug effects*; D003600:Cytosol / Q000378:metabolism*; D005456:Fluorescent Dyes; D016257:Fura-2; D006801:Humans; D009711:Nucleotides / Q000494:pharmacology*; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin; D014544:Uridine Triphosphate / Q000494:pharmacology
D015220:Calcium Channels; D005456:Fluorescent Dyes; D009711:Nucleotides; D013729:Terpenes; C022571:adenosine 5'-O-(3-thiotriphosphate); D000244:Adenosine Diphosphate; D019284:Thapsigargin; D000255:Adenosine Triphosphate; D002217:Carbachol; D000252:Calcium-Transporting ATPases; D002118:Calcium; D016257:Fura-2; D014544:Uridine Triphosphate