The osteoclast Ca2+ receptor is highly sensitive to activation by transition metal cations.
We report changes in the cytosolic Ca2+ concentration ([Ca2+]i) of single rat osteoclasts in response to Ca2+ receptor activation by micromolar concentrations of the transition metal cations, Cd2+ and Ni2+. The extracellular application of Cd2+ or Ni2+ resulted in a concentration-dependent elevation of cytosolic [Ca2+]. Each monophasic [Ca2+]i response consisted of an initial rapid rise of [Ca2+]i to a peak value followed by an exponential decay. Prior application of Cd2+ or Ni2+ induced refractoriness to a second application of the same cation. The results confirm the existence of a divalent cation-sensitive site on the osteoclast showing features of concentration-dependent activation and use-dependent inactivation.
Shankar
V S
VS
Bone and Mineral Metabolism Unit, St. George's Hospital Medical School, London.
Bax
C M
CM
Alam
A S
AS
Bax
B E
BE
Huang
C L
CL
Zaidi
M
M
D000818:Animals; D000831:Animals, Newborn; D002104:Cadmium / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000187:drug effects / Q000378:metabolism*; D002412:Cations; D003600:Cytosol / Q000378:metabolism; D008670:Metals / Q000494:pharmacology*; D009532:Nickel / Q000494:pharmacology*; D010010:Osteoclasts / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D002135:Calcium-Binding Proteins; D002412:Cations; D008670:Metals; D002104:Cadmium; D009532:Nickel; D002118:Calcium