Changes in cytosolic free calcium concentration in isolated rat parotid cells by cholinergic and beta-adrenergic agonists.
The alteration in the concentration of cytosolic free calcium ([Ca2+]i) in isolated rat parotid cells caused by autonomic agents was directly measured using the Ca-sensitive fluorescent probe, quin2. [Ca2+]i of unstimulated cells was estimated to be 162.7 +/- 3.2 nM in normal medium. Carbachol (CCh) and isoproterenol (ISP) caused a rapid rise in [Ca2+]i in a dose-dependent manner. Maximum increases in [Ca2+]i induced by CCh and ISP were approximately 100% and 25% of resting level, respectively. In Ca-free medium, CCh produced a small, rapid rise in [Ca2+]i, followed by a slow decay and a return to resting level within 3-4 min, while all doses of ISP tested failed to change [Ca2+]i. These results suggest that CCh mobilizes Ca2+ from both extracellular and intracellular pools and then results in a rise in [Ca2+]i, whereas ISP may slightly mobilize only the extracellular Ca pool.
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Takemura
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000634:Aminoquinolines; D000681:Amylases / Q000378:metabolism; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism*; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D010277:Parasympathomimetics / Q000494:pharmacology*; D010306:Parotid Gland / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013050:Spectrometry, Fluorescence
D000318:Adrenergic beta-Agonists; D000634:Aminoquinolines; D005456:Fluorescent Dyes; D010277:Parasympathomimetics; D000001:Calcimycin; D002217:Carbachol; D000681:Amylases; D007545:Isoproterenol; C035739:Quin2; D002118:Calcium