title: [Pharmacology of the extracellular calcium ion receptor].
abstract: The calcium sensing receptor (CaSR) belongs to family 3 of G-protein coupled receptors. The CaSR, expressed at the surface of the parathyroid cells, controls parathyroid hormone (PTH) secretion and is the main regulator of calcium homeostasis. Its activity is regulated by small changes in the physiological concentrations of calcium and magnesium ions present in the serum and extracellular fluids, leading to the stimulation of the phospholipases C and A2. Molecules that potentiate the effect of extracellular calcium are called calcimimetics. They reduce the PTH level in vivo and have been proposed to be of therapeutic benefit for the treatment of both primary and secondary hyperparathyroidism. The blocking of CaSR by a calcilytic molecule results in the increase in serum PTH and might be of interest in the treatment of osteoporosis. The CaSR is also expressed in the thyroid, kidney, bone and in neuronal and glial cell populations, where it should be involved in the complex responses associated with calcium and magnesium ions present in the extracellular fluids.
authors.affiliation: Institut de Neurobiologie Alfred Fessard, IFR 2118 CNRS, Laboratoire de Neurobiologie Cellulaire et Moléculaire, UPR 9040, Gif-sur-Yvette, France. ruat@nbcm.cnrs-gif.fr
authors.forename: Martial
authors.initials: M
authors.lastname: Ruat
mesh_terms: D000328:Adult; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D045604:Extracellular Fluid / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000502:physiology; D006706:Homeostasis; D006801:Humans; D006961:Hyperparathyroidism / Q000188:drug therapy; D008274:Magnesium / Q000378:metabolism; D008958:Models, Molecular; D009928:Organ Specificity; D010024:Osteoporosis / Q000188:drug therapy; D010280:Parathyroid Glands / Q000378:metabolism; D010281:Parathyroid Hormone / Q000378:metabolism; D011487:Protein Conformation; D044169:Receptors, Calcium-Sensing / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000502:physiology
chemical_list: D010281:Parathyroid Hormone; D044169:Receptors, Calcium-Sensing; D011993:Recombinant Fusion Proteins; D019204:GTP-Binding Proteins; D008274:Magnesium; D002118:Calcium