Neurotransmitter regulation of cytosolic calcium in osteoblast-like bone cells.
The nervous system may play a role in regulation of bone metabolism. The effects of norepinephrine(NE), vasoactive intestinal peptide(VIP), and ATP on cytosolic Ca2+ were assessed in a rat osteoblast-like osteosarcoma cell line (UMR-106) responsive to PTH. All three transmitters transiently increased Ca2+, with ATP much greater than PTH greater than NE = VIP, and then caused sustained increases in Ca2+. The ATP-induced transient resulted from mobilization of intracellular Ca2+ store, while NE and VIP-induced transients also involved influx of Ca2+. Later sustained increases by all agonists were dependent upon extracellular Ca2+. Release of intracellular Ca2+ by ATP was associated with a marked increase in IP3 but without a significant change in cAMP. NE, VIP, and ATP, through regulation of Ca2+ metabolism, may be involved in various osteoporotic conditions.
Kumagai
H
H
Laboratory of Biological Chemistry, National Institute on Aging, Baltimore, Maryland 21224.
Sakamoto
H
H
Guggino
S
S
Filburn
C R
CR
Sacktor
B
B
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D007295:Inositol Phosphates / Q000378:metabolism; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D014407:Tumor Cells, Cultured; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D007295:Inositol Phosphates; D010281:Parathyroid Hormone; D005576:Colforsin; D014660:Vasoactive Intestinal Peptide; D000255:Adenosine Triphosphate; D011433:Propranolol; D000242:Cyclic AMP; D002118:Calcium; D009638:Norepinephrine; D011224:Prazosin