Possible Interaction: Alprostadil and Calcium Supplement

“STA2 and U46619, TXA2/PGH2 agonists, PGE2/PGE1 , iloprost/PGI2, and thrombin elevated the intracellular concentrations of Ca2+ ([Ca2+]i) , as determined by Fura-2 fluorescence signals.”

“This enzymatic activity is strongly stimulated by NaF and 5'-guanylimidodiphosphate, is slightly stimulated by epinephrine, norepinephrine, isoproterenol, and prostaglandin E1 and is inhibited by calcium.”

“Co‐incubation with prostaglandins E1 and E2 (PGE1, PGE2) (10 μM) but not prostaglandin F2α (PGF2α) (10 μM) significantly inhibited calcium‐ , GTP‐γ‐S and mastoparan‐evoked secretion by 30 – 50%.”

“PGE2 was much more potent than PGE1 and significantly inhibited GTP‐γ‐S‐ and calcium‐evoked … 10 nM and above and mastoparan‐evoked secretion above 1 μM. The inhibitory effects of PGE1 and … calcium‐ , GTP‐γ‐S‐ and mastoparan‐stimulated ACTH secretion … permeabilized cells were pertussis toxin (PTX) sensitive.”

“ PGE1 increased intra‐cellular levels of total inositol phosphates (IP), cyclic GMP, cyclic AMP, and calcium ([Ca2+]i).”

“Exogenously administered PGE1 or PGE2, like atropine, markedly decreased both the flow and calcium concentration of parasympathetically evoked rat parotid saliva; PGF2 alpha was less effective.”

“The results suggest that PGE1 reduces Ca conductance and that this action may underlie its inhibitory action on transmitter release at adrenergic and cholinergic nerve terminals.”

“Instead, PGE1 increases mobilization of Ca++ from the same high affinity La+++-resistant sites affected by Ang III and NE and, in this manner, may increase responses to these two stimulatory agents.”

“From these results it is suggested that (1) in the … must be more dominant than beta-receptors; (2) PGE1 will produce a depolarization of … increase an active transport of calcium ions into smooth muscle cells; and (3) the relaxant responses … an increase in cellular cyclic adenosine monophosphate (AMP) contents.”

“The action of PGE1 was counteracted by decreasing and potentiated by increasing the extracellular calcium concentration.”

“We have investigated the effects of PGE1 in smooth muscle and have demonstrated that while some PGE1 is required for both calcium release and calcium removal , high levels of PGE1 block both processes.”