Size and shape of transverse tubule openings in frog twitch muscle fibers
نویسندگان
چکیده
The openings of transverse tubules in frog twitch fibers are described. The tubules open to the extracellular space by a narrow neck, with an inner diameter of 20 nm. The most peripheral portion of the tubules is tortuous and has a variable diameter. The similarity in size of the openings of T tubules and caveolae and the meandering path of the tubules are sufficient to account for the paucity of observed openings.
منابع مشابه
Alteration of the voltage-dependence of the twitch tension in frog skeletal muscle fibres by a polyether, Bistramide A.
Bistramide A, a toxin isolated from Lissoclinum bistratum Sluiter, was applied to frog skeletal muscle fibres. Micromolar concentrations of toxin decreased the amplitude of the twitch tension. Bistramide A shifted the activation and the steady-state inactivation characteristics of the tension on the voltage axis towards more positive and negative membrane potentials respectively. The data sugge...
متن کاملStructural changes in single muscle fibers after stimulation at a low frequency
Direct stimulation of single muscle fibers from Xenopus laevis at a frequency of 1 Hz results in a decline of the peak isometric twitch tension after about 200 twitches. Fibers were chemically fixed in glutaraldehyde after a varying number of twitches and at several fatigue levels, and the ultrastructural appearance was compared with that of resting fibers treated by identical fixation methods....
متن کاملAnatomical distribution of voltage-dependent membrane capacitance in frog skeletal muscle fibers
Components of nonlinear capacitance, or charge movement, were localized in the membranes of frog skeletal muscle fibers by studying the effect of 'detubulation' resulting from sudden withdrawal of glycerol from a glycerol-hypertonic solution in which the muscles had been immersed. Linear capacitance was evaluated from the integral of the transient current elicited by imposed voltage clamp steps...
متن کاملCa " Dependence of Transverse Tubule - mediated Calcium Release in Skinned Skeletal Muscle Fibers
Isometric force and "Ca efflux from the sarcoplasmic reticulum were measured at 19°C in frog skeletal muscle fibers skinned by microdissection . After Ca" loading, application of the ionophores monensin, an Na+(K+)/ H' exchanger, or gramicidin D, an H+ > K' > Na' channel-former, evoked rapid force development and stimulated release of ^"30% of the accumulated "Ca within 1 min, whereas CCCP (car...
متن کاملS T U D I E S OF T H E T R I A D IV. Structure of the Junction in Frog Slow Fibers
The structure of the triadic junction in frog slow fibers has been studied and compared with that of twitch fibers. The junct ional gap is wider (by approximately 13 %) in slow fibers. The junct ional feet have the same size and disposition as in twitch fibers, al though the size and shape of the junct ional areas are different. I t is concluded that the role of triads in slow fibers is the sam...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The Journal of Cell Biology
دوره 64 شماره
صفحات -
تاریخ انتشار 1975