Cyclic adenosine monophosphate-dependent activation of transient receptor potential vanilloid 4 (TRPV4) channels in osteoblast-like MG-63 cells.

Parathyroid hormone (PTH) directly interacts with bone remodeling osteoblasts and osteocytes expressing the G-protein coupled receptor PTH receptor 1 (PTH1R), and its osteoanabolic effects mostly involve the cAMP/PKA signaling cascade. Considering that PTH-dependent calcium entry in rat enterocytes is reproduced by the adenylate cyclase agonist forskolin or by cAMP analogues, possible involvement of calcium as a second messenger in PTH-dependent cAMP signaling was investigated in MG-63 cells. First, Ca influx was confirmed in Fluo3-loaded MG-63 cells treated with a cell-permeable cAMP analog.