How does smooth muscle contraction occur?
Smooth muscle contractile mechanism is slightly different form the cardiac and skeletal muscle. They all need the interaction between myosin and actin but one important difference is, smooth muscle does not have troponin and tropomyosin. So in smooth muscle for myosin to interact with actin, myosin must be phosphorylated.
who phosphorylate the myosin?
We all know phosphorylation is done by an enzyme called kinase, so here the enzyme is called myosin light chain kinase. That means if the myosin light chain kinase is inhibited then it won’t be able to phosphorylate myosin and then there is no interaction between the myosin and actin, hence we have relaxation of smooth muscle.
How do we inhibit myosin light chain kinase?
As we all know, phosphorylation of an enzyme will either activated or inhibit the enzyme, so here phosphorylation of myosin light chain kinase will result in inactivation.
How do we phosphorylate myosin light chain kinase?
There are several mechanisms. Increasing cAMP will result in increased level of Protein kinase A. the kinase will phosphorylate the myosin light chain kinase. This is how beta-2 adrenergic causes relaxation of bronchial smooth muscle and blood vessels.
How does nitric oxide dilate blood vessels?
Nitric oxide dilate blood vessels by binding to intra cytoplasmic Guanylate cyclase, which will convert GTP to cGMP and it in turn activates Protein Kinase G. the PKG will phosphorylate the Myosine light chain kinase and inactivate it.
How does milrinone cause blood vessels to dilate?
Milrinone is phosphodiestrase inhibitor. Phosphodiesterase inhibit cAMP. so if you inhibit Phosphodiesterase then cAMP is free to activate PKA. PKA will phosphorylate myosine light chain kinase and inactivate it. If myosin is not phosphorylated it cannot interact with actin, which means relaxation of smooth muscle.
Smooth muscle contractile mechanism is slightly different form the cardiac and skeletal muscle. They all need the interaction between myosin and actin but one important difference is, smooth muscle does not have troponin and tropomyosin. So in smooth muscle for myosin to interact with actin, myosin must be phosphorylated.
who phosphorylate the myosin?
We all know phosphorylation is done by an enzyme called kinase, so here the enzyme is called myosin light chain kinase. That means if the myosin light chain kinase is inhibited then it won’t be able to phosphorylate myosin and then there is no interaction between the myosin and actin, hence we have relaxation of smooth muscle.
How do we inhibit myosin light chain kinase?
As we all know, phosphorylation of an enzyme will either activated or inhibit the enzyme, so here phosphorylation of myosin light chain kinase will result in inactivation.
How do we phosphorylate myosin light chain kinase?
There are several mechanisms. Increasing cAMP will result in increased level of Protein kinase A. the kinase will phosphorylate the myosin light chain kinase. This is how beta-2 adrenergic causes relaxation of bronchial smooth muscle and blood vessels.
How does nitric oxide dilate blood vessels?
Nitric oxide dilate blood vessels by binding to intra cytoplasmic Guanylate cyclase, which will convert GTP to cGMP and it in turn activates Protein Kinase G. the PKG will phosphorylate the Myosine light chain kinase and inactivate it.
How does milrinone cause blood vessels to dilate?
Milrinone is phosphodiestrase inhibitor. Phosphodiesterase inhibit cAMP. so if you inhibit Phosphodiesterase then cAMP is free to activate PKA. PKA will phosphorylate myosine light chain kinase and inactivate it. If myosin is not phosphorylated it cannot interact with actin, which means relaxation of smooth muscle.
0 comments
Post a Comment