Prostaglandin for PDA? How come?

[MudPhud20XX]

Hi all, so as far as I know, prostaglandin increases smooth muscle contraction and to me this seems to be contradicting to the fact that prostaglandin or its analog (alprostadil) is used for Patent Ductus Arteriosus because of there vasodilatory effect which is the result of smooth muscle relaxation not contraction.

So prostaglandin does both smooth muscle contraction and relaxation?

If so, is this effect organ/location/tissue specific? Many thanks in advance.

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[Apoplexy__]

In most cases, PG's cause vasodilation. The main exception I can think of is uterine contractions: PGE2 and PGF2 cause smooth muscle contraction. Examples: Misoprostol contraindicated in pregnancy, and indomethacin was experimented with as a delayer of labor.

Maybe someone else can think of other exceptions, but for the most part, just remember that prostaglandins are primarily responsible for vasodilation.

 

[sanj238]

Hi all, so as far as I know, prostaglandin increases smooth muscle contraction and to me this seems to be contradicting to the fact that prostaglandin or its analog (alprostadil) is used for Patent Ductus Arteriosus because of there vasodilatory effect which is the result of smooth muscle relaxation not contraction.

So prostaglandin does both smooth muscle contraction and relaxation?

If so, is this effect organ/location/tissue specific? Many thanks in advance.

It depends on the specific type of prostaglandin available. Think about where they come from- Arachadonic Acid- and a variety of types can be made depending on the cell involved. the different types of prostaglandins include prostacycline PGI, PGE1, Prostaglandin 2 or PGE2 and PGF2alpha.

PGF and PGE2 are basically the same in that they both are important for contraction- they are as a result used as abortifactants along with mifipristone- combined with dinoprostol or RU486 (or something). Furthermore, PGF can be used to reduce IOP in glaucoma- latanoprost. Finally- NSAIDS are given for primary amenorrhea because it is thought inhibiting PGF can lead to increased blood flow. Similarly carboprost is used to treat excess postpartum bleeding by causing contractions of uterine.

PGE1 has two functions it causes vasodilation and it also causes increased mucous secretion. PGE1 or misoprostol (not to be confused with mifipristone) is used to treat PUD. PGE1 is also used for heart problems because it helps maintain opneing by dialtion- alprostadil. Similarly alprostadil was used for ED

Prostacyclines or PGI function to stabilize platelets by decreasing the number of calcium channels open via ad cyclase- increases calcium vacuum pumps (yes I call them vacuum pumps whatever)- decreasing the ability to activate platelet aggreation via Gp1b

prostacyclins also cause vasodilation.

You know- you can find the answer to this information online.

 

[MudPhud20XX]

Thank you guys!