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.
Slow waves cause no smooth muscle contraction.When the amplitude of slow waves in smooth muscle cells reaches a certain thresholdâthe slow-wave threshold âa particular membrane ion channel, L-type Ca 2+ channels, are activated, resulting in calcium influx and initiation of motility.low waves cause no smooth muscle contraction.When the amplitude of slow waves in smooth muscle cells reaches a certain thresholdâthe slow-wave threshold âa particular membrane ion channel, L-type Ca 2+ channels, are activated, resulting in calcium influx and initiation of motility.