{"@type": "dcat:Dataset", "accessLevel": "public", "bureauCode": ["009:25"], "contactPoint": {"@type": "vcard:Contact", "fn": "NIH", "hasEmail": "mailto:info@nih.gov"}, "description": "Background\n          The multisubunit (\u03b11S,\u03b12-\u03b4, \u03b21a and \u03b31) skeletal muscle dihydropyridine receptor (DHPR) transduces membrane depolarization into release of Ca2+ from the sarcoplasmic reticulum (SR) and also acts as an L-type Ca2+ channel. To more fully investigate the function of the \u03b31 subunit in these two processes, we produced mice lacking this subunit by gene targeting.\n        \n        \n          Results\n          Mice lacking the DHPR \u03b31 subunit (\u03b31 null) survive to adulthood, are fertile and have no obvious gross phenotypic abnormalities. The \u03b31 subunit is expressed at approximately half the normal level in heterozygous mice (\u03b31 het). The density of the L-type Ca2+ current in \u03b31 null and \u03b31 het myotubes was higher than in controls. Inactivation of the Ca2+ current produced by a long depolarization was slower and incomplete in \u03b31 null and \u03b31 het myotubes, and was shifted to a more positive potential than in controls. However, the half-activation potential of intramembrane charge movements was not shifted, and the maximum density of the total charge was unchanged. Also, no shift was observed in the voltage-dependence of Ca2+ transients. \u03b31 null and \u03b31 het myotubes had the same peak Ca2+ amplitude vs. voltage relationship as control myotubes.\n        \n        \n          Conclusions\n          The L-type Ca2+ channel function, but not the SR Ca2+ release triggering function of the skeletal muscle dihydropyridine receptor, is modulated by the \u03b31 subunit.", "distribution": [{"@type": "dcat:Distribution", "description": "Visit the original government dataset for complete information, documentation, and data access.", "downloadURL": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC37314/", "mediaType": "text/html", "title": "Official Government Data Source"}], "identifier": "https://healthdata.gov/api/views/axry-raze", "issued": "2025-07-14", "keyword": ["calcium-channel", "dihydropyridine-receptor", "gene-targeting", "muscle-contraction", "nih"], "landingPage": "https://healthdata.gov/d/axry-raze", "modified": "2025-09-06", "programCode": ["009:048"], "publisher": {"@type": "org:Organization", "name": "National Institutes of Health"}, "theme": ["NIH"], "title": "Modulation of L-type Ca"}