title: Purinergic (P2) receptor-operated calcium entry into rat thyroid cells.
abstract: In the epithelial cell line FRT, derived from rat thyroid, extracellular ATP, at a concentration as low as 1 x 10(-7) M, specifically increases cytosolic Ca++ two fold over the basal level of 255 +/- 45 nM. A maximum increase of 5 fold over basal is seen at 1 x 10(-5) M ATP. The effect occurs in the absence of any measurable phosphatidyl inositol metabolism and requires the presence of extracellular Ca++, but is independent of extracellular Na+; it is duplicated by ATP gamma S but not by adenosine, AMP, ADP, AMP-PNP, AMP-CPP, or AMP-PCP. In the presence of the P2-receptor antagonist suramin, the ATP induced Ca++ influx is completely inhibited, whereas Mg++, La , and verapamil are ineffective. It appears that the most likely (and unique) mechanism of ATP induced increase of cytosolic Ca++ in FRT cells in an increased influx through the activation of a P2 receptor operated Ca++ channel.
authors.affiliation: Department of Clinical Physiology, Walter Reed Army Institute of Research, Washington, D.C. 20307-5100.
authors.forename: S M
authors.initials: SM
authors.lastname: Aloj
authors.forename: D
authors.initials: D
authors.lastname: Liguoro
authors.forename: J G
authors.initials: JG
authors.lastname: Kiang
authors.forename: R C
authors.initials: RC
authors.lastname: Smallridge
mesh_terms: D000227:Adenine Nucleotides / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D004963:Estrenes / Q000494:pharmacology; D005456:Fluorescent Dyes; D007211:Indoles; D007295:Inositol Phosphates / Q000378:metabolism; D007700:Kinetics; D011760:Pyrrolidinones / Q000494:pharmacology; D051381:Rats; D011983:Receptors, Purinergic / Q000187:drug effects / Q000502:physiology*; D013050:Spectrometry, Fluorescence; D013961:Thyroid Gland / Q000187:drug effects / Q000378:metabolism*; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors
chemical_list: D000227:Adenine Nucleotides; D004963:Estrenes; D005456:Fluorescent Dyes; D007211:Indoles; D007295:Inositol Phosphates; D011760:Pyrrolidinones; D011983:Receptors, Purinergic; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C059587:Indo-1 pentaacetoxymethyl ester; D000255:Adenosine Triphosphate; D010738:Type C Phospholipases; D002118:Calcium