Summary
The goal of the present investigation was to compare quantitatively the distribution of T-tubules between regions of the myocardium. The volume fraction and surface density of T-tubules in rabbit right atrial free wall, left atrial free wall, right ventricular free wall, left ventricular free wall, right ventricular papillary muscle, and left ventricular papillary muscle were measured using established, electron-microscopic, morphometric techniques. T-tubules were delineated using wheat-germ agglutinin conjugated to horseradish peroxidase as a tracer. No significant differences were found in the morphometric parameters between any two ventricular samples or between atrial samples. Furthermore, little difference between T-tubule volume fraction or surface density was found between individual animals for any given site. Both volume fraction and surface density of ventricular T-tubules were more than ten-times their values in atrial tissue (volume fraction: 3.43%±0.35 vs. 0.20±0.09; surface density: 2.46 μm2/μm3±0.11 vs 0.10±0.04). Measurements show that there is greater variation of T-tubule volume fraction and surface density within atrial samples than within ventricular samples. This suggests greater inhomogeneity in T-tubule distribution in atrial myocardium than in ventricular myocardium. Morphometric data also indicate that the mean diameter of atrial T-tubules is greater than that of ventricular T-tubules while qualitative observations show that atrial T-tubules are distributed less regularly and have a larger longitudinal component to their organization than those in the ventricular myocardium.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Almers W, Fink R, Palade PT (1981) Calcium depletion in frog muscle tubules: the decline of calcium current under maintained depolarization. J Physiol 312:177–207
Ayettey AS, Navaratnam V, Yates RD (1988) Ultrastructure of the internodal myocardium in the rat. J Anat 158:77–90
Bossen EH, Sommer JR, Waugh RA (1978) Comparative stereology of the mouse and finch left ventricle. Tissue Cell 10:773–784
Bossen EH, Sommer JR, Waugh RA (1981) Comparative stereology of mouse atria. Tissue Cell 13:71–77
Fawcett DW, McNutt NS (1969) The ultrastructure of the cat myocardium. I. Ventricular papillary muscle. J Cell Biol 42:1–45
Forbes MS, Sperelakis N (1984) Ultrastructure of mammalian cardiac muscle. In: Sperelakis N (ed) Physiology and pathophysiology of the heart. Nijhoff, Boston The Hague, pp 3–42
Forbes MS, Van Neil EE (1988) Membrane systems of guinea pig myocardium: Ultrastructure and morphometric studies. Anat Rec 222:362–379
Forssmann WG, Girardier L (1970) A study of the T system in rat heart. J Cell Biol 44:1–19
Huxley HE (1964) Evidence for continuity between the central elements of the triads and the extracellular space in frog sartorius muscle. Nature 202:1067–1071
Krüger P (1952) Tetanus and Tonus der quergestreiften Skelettmuskeln der Wirbeltiere und des Menschen. Akademische Verlagsgesellschaft, Leipzig
Lai FA, Anderson K, Rousseau E, Liu QY, Meissner G (1988) Evidence for a Ca2+ channel within the ryanodine receptor complex from cardiac sarcoplasmic reticulum. Biochem Biophys Res Commun 151:441–449
McNutt NS, Fawcett DW (1969) The ultrastructure of the cat myocardium. II. Atrial muscle. J Cell Biol 42:46–67
Page SG (1969) Structure and some contractile properties of fast and slow muscle of the chicken. J Physiol 205:131–145
Page E, McCallister LP (1973) Studies on the intercalated disk of rat left ventricular myocardial cells. J Ultrastruct Res 43:388–411
Page E, McCallister LP, Power B (1971) Stereological measurements of cardiac ultrastructures implicated in excitation-contraction coupling. Proc Natl Acad Sci USA 68:1464–1466
Page E, Earley J, Power B (1974) Normal growth of ultrastructures in rat left ventricular myocardial cells. Circ Res 34 [Suppl]:12–16
Sommer JR, Johnson EA (1979) Ultrastructure of cardiac muscle. In: Berne RM, Sperelakis N, Geiger SR (eds) Handbook of physiology, the cardiovascular system, sect 2, vol 1, American Physiological Society, Bethesda, pp 61–100
Stewart JM, Page EM (1978) Improved stereological techniques for studying myocardial cell growth: Application to external sarcolemma, T system, and intercalated disks of rabbit and rat hearts. J Ultrastruct Res 65:119–134
Tidball JG, Gadus MV (1988) Cytochemical, histological and phylogenetic distribution of a 38,000-dalton protein associated with transverse tubules. J Cell Biochem 38:99–112
Tidball JG, Smith R, Shattock MJ, Bers DM (1988) Differences in action potential configuration in ventricular trabeculae correlate with differences in density of transverse tubule: sarcoplasmic reticulum couplings. J Mol Cardiol 20:539–546
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Tidball, J.G., Cederdahl, J.E. & Bers, D.M. Quantitative analysis of regional variability in the distribution of transverse tubules in rabbit myocardium. Cell Tissue Res 264, 293–298 (1991). https://doi.org/10.1007/BF00313966
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00313966