| During mammalian heart development, in adult myocardium, depolarization of the sarcolemmal (SL) and T-tubule membranes activates L-type Ca 2+ channels/dihydropyridine receptors (DHPR) which results in a small influx of Ca2+ that is amplified by Ca2+-induced Ca2+ release (CICR) from the sarcoplasmic reticulurn (SR). A major structural specialization of the SL is couplings with the SR. Dyadic couplings are formed between ryanodine receptor (RyR) and either the SL or the T-tubular DHPR.;In this study, subcellular geometric distribution and degree of colocalization of DHPR and RyR were determined in neonatal rabbit ventricular myocytes aged 3--20 days. Isolated myocytes were obtained by enzyme digestion of the heart. Fixed and permeabilized myocytes were incubated with primary antibodies against DHPR and RyR followed by labeling with fluorescently tagged secondary antibodies. Confocal microscopy and also widefield-deconvolution technique were used to generate 3-dimensional images of DHPR and RyR localization within myocardial cells. (Abstract shortened by UMI.). |
