Membrane vesicles enriched in both ryanodine receptor and dihydropyridine receptor were obtained from rabbit skeletal muscle and solubilized with 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate. Analysis of the sedimentation behavior of the solubilized proteins showed the existence of a population of alpha 1 subunits of the dihydropyridine receptor which cosedimented with the ryanodine receptor. Solubilized proteins were immunoprecipitated with antibodies directed against either the ryanodine receptor or the alpha 1, alpha 2, or beta subunits of the dihydropyridine receptor. Immunoprecipitated proteins were identified by Western blot analysis and by specific labeling with [3H]ryanodine or [3H]PN200-110. Immunoprecipitation of the solubilized proteins with antibodies directed against the dihydropyridine receptor led to the coimmunoprecipitation of the ryanodine receptor. Conversely, immunoprecipitation with antibodies directed against the ryanodine receptor led to an immune complex containing both receptors, but these antibodies were unable to precipitate purified dihydropyridine receptor. These results demonstrate that ryanodine receptor and dihydropyridine receptor are present in the triad membrane preparation in a complex which may play an important role in excitation-contraction coupling.
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http://dx.doi.org/10.1073/pnas.91.6.2270 | DOI Listing |
Reprod Sci
January 2025
Department of Physiology, College of Graduate Studies, Midwestern University, Downers Grove, IL, 60515, USA.
The experience of pregnancy affects uterine function well beyond delivery. We previously demonstrated that the response to oxytocin is more robust in the uteri of proven breeder rats. This study investigates the contribution of T-type calcium channels (TTCCs) and L-type calcium channels (LTCCs) to the distinct response of virgin (V) and proven breeder (PB) rat uteri to oxytocin.
View Article and Find Full Text PDFAm J Physiol Lung Cell Mol Physiol
January 2025
Smooth Muscle Research Centre, Dundalk Institute of Technology, Dublin Road, Dundalk, Co. Louth, Ireland.
Cholinergic tone is elevated in obstructive lung conditions such as COPD and asthma, but the cellular mechanisms underlying cholinergic contractions of airway smooth muscle (ASM) are still unclear. Some studies report an important role for L-type Ca channels (LTCC) and Ano1 Ca-activated Cl™ channels (CACC) in these responses, but others dispute their importance. Cholinergic contractions of ASM involve activation of M3Rs, however stimulation of M2Rs exerts a profound hypersensitisation of these responses.
View Article and Find Full Text PDFPharmaceuticals (Basel)
November 2024
Division of Physiology, Department of Pharmacology, Physiology, and Microbiology, Karl Landsteiner University of Health Sciences, 3500 Krems, Austria.
Int J Mol Sci
December 2024
Institute of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Biochemical and Pharmacological Center (BPC) Marburg, University of Marburg, 35032 Marburg, Germany.
encodes the α1c subunit of the L-type Ca channel, Cav1.2. Ventricular myocytes from haploinsufficient () rats exhibited reduced expression of Cav1.
View Article and Find Full Text PDFBiomedicines
December 2024
Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA.
Peptide Lv is a small endogenous secretory peptide with ~40 amino acids and is highly conserved among certain several species. While it was first discovered that it augments L-type voltage-gated calcium channels (LTCCs) in neurons, thus it was named peptide "Lv", it can bind to vascular endothelial growth factor receptor 2 (VEGFR2) and has VEGF-like activities, including eliciting vasodilation and promoting angiogenesis. Not only does peptide Lv augment LTCCs in neurons and cardiomyocytes, but it also promotes the expression of intermediate-conductance K channels (K3.
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