MY DOG IS BROKEN!

Presented by: Nicole L., Marvi C.

The Problem

Other then the fact that Tessa bought a champion Yorkshire terrier for an asinine amount, her dog, Akira Edelweiss, has erectile dysfunction.

She asked her friend, Melody, about the possible problems that Akira could have been suffering. And so, Melody suggests: Akira cannot have an erection because

erections, which are controlled by cell signaling pathways, and there may be a malfunction with cell signaling pathways within Akira.

Cell Signaling Pathway

Steps of Signaling Pathway

Step One:

The nitric oxide activates the guanylyl cyclase (which was initially inactive) and becomes N:O guanylyl cyclases which is now active. The guanylyl cyclase was the receptor and

the nitric oxide is the signaling molecule.

Steps of Signaling Pathway

Step Two

The activation of the N:O-Guanylyl cyclase causes a protein to bind with GTP and a subunit to guanylyl cyclase.

The binding of the subunit to the guanylyl cyclase promotes the synthesis of cGMP.

Steps of Signaling Pathway

Step Three

cGMP binds to subunits of PKG, releasing the catalytic subunits of PKG and turning the once inactive PKG active.

Steps of Signaling Pathway

Step Four

The activated PKG is phosphorylated and become phospho-proteins.

The phospho-proteins lead to the lowering of Ca2+ as well as the desensitization to Ca2+.

Steps of Signaling Pathway

Step Five

The lowering of the Ca2+ and desensitization of Ca2+ then leads to the relaxation of the smooth muscles.

The smooth muscles, which make up the vascular system, relax and let blood flow through the blood vessels increase and lead to the erectile stimulation.

Suggestions from Melody

She suggests two things for Tessa’s dog to solve his problem of erectile dysfunction: Viagra

The Viagra would work on phosphodieterase, which acts on cyclic guanosine monophosphate, therefore breaking it down and deactivating it.

Ginseng Ginseng acts on the nitric oxide in the cell

signaling pathway that leads to erection.

Viagra

The effects of Viagra, as stated before, is to work on phosphodieterase (PDE).

The PDE break downs and deactivates cGMP, the more PDE there is, the more the blood flow is constricted.

Steps of Signaling Path - Viagra When the PDE is there, it breaks down

cGMP. The cGMP cannot activate PKG. The PKG cannot lead to the lowering of

Ca2+ levels. And, because the Ca2+ is not lowered,

relaxation increases.

Ginseng

It helps produce more nitric acid (the signaling molecule).

More nitric acid, more guanylylcyclase is activated, more cGMP produced.

With the more PKG produced, it increases Ca2+, which increases the relaxation rather than the contraction.