The FDA first approved Invokana as the first SGLT2 drug in March 2013. Since then, it has become a cash cow for J&J and its Janssen Pharmaceuticals unit. In the first quarter of 2015, the drug already brought in $278 million, triple what it made last year.
During contraction, the smooth-muscle cell's intermediate filaments help to draw the cell up, like closing a drawstring purse. Calcium ions regulate contraction in smooth muscle, but they do it in a slightly different way than in skeletal muscle: 1  Calcium ions come from outside of the cell.2  Calcium ions bind to an enzyme complex on myosin, called calmodulin-myosin light chain kinase. Calcium ions come from outside of the cell. 2  Calcium ions bind to an enzyme complex on myosin, called calmodulin-myosin light chain kinase. 3  The enzyme complex breaks up ATP into ADP and transfers the P i directly to myosin. 4  This P i transfer activates myosin.
Excitation-Contraction coupling & contraction in smooth muscle. Excitation-Contraction Coupling: Some of the most important differences between skeletal muscle and smooth muscle occur in excitation-contraction coupling.One element that is the same between the two forms of muscle is that calcium plays a starring role.Unfortunately, that is about the extent of the similarities.Smooth muscle differs in: the source of the calcium (relying both on extracellular and intracellular sources). how the release of the calcium into the intracellular space is accomplished (the control), and how the calcium is used to initiate the contraction.nfortunately, that is about the extent of the similarities. Smooth muscle differs in: the source of the calcium (relying both on extracellular and intracellular sources). how the release of the calcium into the intracellular space is accomplished (the control), and how the calcium is used to initiate the contraction.