| [ Summary ] |
Ca is a major divalent cation, serving as a key extracellular and intracellular messenger, absorbed through the duodenum and reabsorbed in the renal distal tubules. TRPV5 and 6 are Ca-permeable channels found in these epithelia, producing a gate for transcellular Ca transport with calbindin 28. Ca reabsorption is regulated from ATL to DCT under influence of calcitonin, PTH and vitamin D3. TRPV5, 6 mRNA are up-regulated by vitamin D3 but not by the other two. They reveal a higher selectivity of Ca among the Trp family and encode inwardly rectified currents. The nomenclature may be confusing, with terms such as ECaC1, 2 and CaT1, 2 being used for the two groups. We discussed the results raised concerning them and the need to clarify their physiological or clinical relevance. |