Title: T-tubule | Psychology Wiki | Fandom
Headings: T-tubule
T-tubule
Contents
Structure
Excitation-contraction coupling
Detubulation
See also
External links

Content: The L-type calcium channels in T-tubules activate in response to electrical stimulation; their opening allows calcium to flow down its electrochemical gradient and into the cell. Activation of the L-type channel also causes a mechanical interaction between it and calcium-release channels located on the adjacent sarcoplasmic reticulum membrane. In skeletal muscle, the influx of calcium through the L-type calcium channel on the T-tubule contributes little to excitation-contraction coupling, whereas it is crucial to the proper function of cardiac muscle ( see Cardiac action potential ). Conversely, the mechanical interaction between the T-tubule's L-type calcium channel and the calcium-release channel is critical to proper skeletal muscle contraction, whereas it contributes little to the contraction of cardiac muscle. Detubulation
It is possible to physically and functionally uncouple T-tubules from the surface membrane using a technique known as detubulation. This relies on osmotically active chemicals, such as glycerol (for skeletal muscle) or formamide (mainly for cardiac muscle ). Addition of these chemicals to the solution surrounding muscle cells causes the cells to shrink; when the chemical is withdrawn the cells rapidly expand before returning to their normal size. The rapid expansion is thought to cause the t-tubules to detach from the surface membrane, which reseals, and to reseal within the cell.