Adrenoreceptor mobilization of calcium in rat submandibular cells.
The stimulation of adrenoreceptors by epinephrine leads to an alteration in the Ca2+ homeostasis of rat submandibular cells. The relative contributions of alpha- and beta-adrenoreceptors were assessed with specific adrenergic agents. Stimulation of alpha 1-adrenoreceptors resulted in enhanced unidirectional 45Ca2+ fluxes, while such effects following beta-adrenoreceptor stimulation, though suggestive, were equivocal. When the cytosolic Ca2+ level was followed in cells pre-loaded with the Ca2+-sensitive fluorescent indicator Quin 2, clear results were observed. Both alpha 1- and beta-adrenoreceptor stimulation were capable of mobilizing intracellular and extracellular Ca2+ pools, as assessed by differential responses of cells incubated in media (+/-)-ethylene-glycol-bis-(beta-aminoethyl ether)-N,N'-tetraacetic acid. However, Ca2+ mobilization following alpha 1-adrenoreceptor stimulation was more rapid (initial rate approximately 4-5 X) and to a greater extent (approximately 2 X) than seen with beta-adrenoreceptor stimulation.
Clinical Investigations and Patient Care Branch, National Institute of Dental Research, Bethesda, MD 20892.
J
J
Helman
I S
IS
Ambudkar
B J
BJ
Baum
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D002217:Carbachol / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D004837:Epinephrine / Q000494:pharmacology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D011224:Prazosin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000378:metabolism*; D013363:Submandibular Gland / Q000166:cytology / Q000378:metabolism*; D015016:Yohimbine / Q000494:pharmacology
D002132:Calcium Radioisotopes; D011941:Receptors, Adrenergic; D015016:Yohimbine; D002217:Carbachol; D011433:Propranolol; D007545:Isoproterenol; D002118:Calcium; D011224:Prazosin; D004837:Epinephrine