My dog is broken! biolab 2010Presentation Transcript
My dog is broken! By: Erica Choi and Christina Datuin
The Process of Erection Nitric Oxide enters the cell (binds to an intracellular receptor) GuanylylCyclase becomes active when Nitric Oxide binds to its receptor Binding of nitric oxide promotes the synthesis of cGMP from GTP cGMP binds to the regulatory subunit, which makes an inactive PKG, active! Activated PKG uses proteins and ATP to create Phospho-proteins that lower the concentration of Ca2+ This lowering of CA2+ causes the smooth muscle cells in the penis to relax, allowing blood to flow into the penis, which then leads to contracting aka erection!
Ginseng and Nitric Oxide Ginseng helps produce more nitric oxide, which is the signaling molecule in this case. More nitric oxide means that more guanylylcyclase is activated and more cGMP is produced. Thus activating more PKG, lowering the CA2+ concentration, and eventually leading to more relaxation and then more of a contraction.
Viagra and PDE5 PDE5 is an inhibitor that prevents the breakdown of cGMP by phosphodiesterase. Since it binds at the allosteric site opposed to the catalytic site, it does not have to compete with the signaling molecules. Since Viagra enhances erection it stops the PDE5 inhibitor from working so that there will be more cGMP, leading to more PKG, less CA2+, more blood flow, and then more relaxation and contraction.
What else could it be? If Viagra and Ginseng don’t work, what could be the problem? Well the IP3 receptor could be activated, therefore opening a calcium channel which results in the release of Ca2+ into the cytoplasm. Phospholamban also regulates the Ca2+ channels in the muscle cells. During relaxation phospholamban is phosphorylated by kinase, removing the inhibition and restoring low calcium levels in the cytoplasm. MLC phosphatase prevents relaxation and controls the components of the Ca2+ independent pathway. PKG prevents the flow of Ca2+ into the cell, as does the K+ channel. An increase of Ca2+ decreases the relaxation of the smooth muscle cells in the penis, therefore preventing contraction. If any of these proteins are malfunctioning, this could be the cause of erectile dysfunction.