In my book Principles of Physiology (by Debasis Pramanik), it is mentioned that dipyridamole inhibits phosohodiesterase which increases cyclic adenosine monophosohate (cAMP) which potentiates prostacyclin (prostaglandin I2 or PGI2).
Can someone show me the relationship between phosphodiesterase, cAMP and PGI2?
Basically, the signal transduction pathway of PGI2 involves a Gs protein. This Gs protein involves the increase in cAMP (through adenylate cyclase; I am assuming you know the signal transduction pathways). Thus, when you administer Dipyridamole, phosphodiesterase is inhibited (which would've degraded your cAMP), thus there is an augmented effect of the PGI2.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3085271/ Go through this article and check out the first image there. On the very left of the image, you can find the PGI2 pathway. Hope this helps :)
