Relationship between cAMP and Ca2+ fluxes in human platelet membranes

Mechanisms involved in the antiplatelet effect of C-phycocyanin

“…Our result indicated that the rise of [Ca 2þ ] i of platelets evoked by AA was significantly reduced by cpc in the presence of extracellular calcium (1 mM) or in the Ca 2þ -free solution cpc, implying that the inhibition of intracellular Ca 2þ mobilization may be due to attenuation of calcium influx and calcium release from intracellular calcium stores. In addition, cyclic AMP also lowers platelet [Ca 2þ ] i by stimulating Ca 2þ extrusion from cells and uptake of cytosolic Ca 2þ into the dense tubular system (Feinstein et al 1985;Enouf et al 1987). Thus, the enhancement of cyclic AMP level by cpc may be also involved in the suppression of platelet intracellular Ca 2þ mobilization.…”

Mechanisms involved in the antiplatelet effect of C-phycocyanin

“…Our result indicated that the rise of [Ca 2þ ] i of platelets evoked by AA was significantly reduced by cpc in the presence of extracellular calcium (1 mM) or in the Ca 2þ -free solution cpc, implying that the inhibition of intracellular Ca 2þ mobilization may be due to attenuation of calcium influx and calcium release from intracellular calcium stores. In addition, cyclic AMP also lowers platelet [Ca 2þ ] i by stimulating Ca 2þ extrusion from cells and uptake of cytosolic Ca 2þ into the dense tubular system (Feinstein et al 1985;Enouf et al 1987). Thus, the enhancement of cyclic AMP level by cpc may be also involved in the suppression of platelet intracellular Ca 2þ mobilization.…”

Activation of the murine EP3 receptor for PGE2 inhibits cAMP production and promotes platelet aggregation

“…We suggest that the concentration of PGE 2 in the local environment modifies the intracellular level of cAMP, which in turn determines the response of the platelets to aggregating agents. Current literature suggests that the intracellular concentration of cAMP determines the extent of PKA activation, which is one pathway for regulating the availability of cytosolic calcium and phosphorylation of myosin (29)(30)(31)(32) (Figure 5a). We next sought to determine whether the role of the EP3 receptor in modifying the response of platelets could be observed in vivo.…”

Mechanisms involved in the antiplatelet effect of C-phycocyanin

“…Our result indicated that the rise of [Ca 2þ ] i of platelets evoked by AA was significantly reduced by cpc in the presence of extracellular calcium (1 mM) or in the Ca 2þ -free solution cpc, implying that the inhibition of intracellular Ca 2þ mobilization may be due to attenuation of calcium influx and calcium release from intracellular calcium stores. In addition, cyclic AMP also lowers platelet [Ca 2þ ] i by stimulating Ca 2þ extrusion from cells and uptake of cytosolic Ca 2þ into the dense tubular system (Feinstein et al 1985;Enouf et al 1987). Thus, the enhancement of cyclic AMP level by cpc may be also involved in the suppression of platelet intracellular Ca 2þ mobilization.…”

Activation of the murine EP3 receptor for PGE2 inhibits cAMP production and promotes platelet aggregation

“…We suggest that the concentration of PGE 2 in the local environment modifies the intracellular level of cAMP, which in turn determines the response of the platelets to aggregating agents. Current literature suggests that the intracellular concentration of cAMP determines the extent of PKA activation, which is one pathway for regulating the availability of cytosolic calcium and phosphorylation of myosin (29)(30)(31)(32) (Figure 5a). We next sought to determine whether the role of the EP3 receptor in modifying the response of platelets could be observed in vivo.…”

Mechanisms involved in the antiplatelet effect of C-phycocyanin

“…Our result indicated that the rise of [Ca 2þ ] i of platelets evoked by AA was significantly reduced by cpc in the presence of extracellular calcium (1 mM) or in the Ca 2þ -free solution cpc, implying that the inhibition of intracellular Ca 2þ mobilization may be due to attenuation of calcium influx and calcium release from intracellular calcium stores. In addition, cyclic AMP also lowers platelet [Ca 2þ ] i by stimulating Ca 2þ extrusion from cells and uptake of cytosolic Ca 2þ into the dense tubular system (Feinstein et al 1985;Enouf et al 1987). Thus, the enhancement of cyclic AMP level by cpc may be also involved in the suppression of platelet intracellular Ca 2þ mobilization.…”

Activation of the murine EP3 receptor for PGE2 inhibits cAMP production and promotes platelet aggregation

“…We suggest that the concentration of PGE 2 in the local environment modifies the intracellular level of cAMP, which in turn determines the response of the platelets to aggregating agents. Current literature suggests that the intracellular concentration of cAMP determines the extent of PKA activation, which is one pathway for regulating the availability of cytosolic calcium and phosphorylation of myosin (29)(30)(31)(32) (Figure 5a). We next sought to determine whether the role of the EP3 receptor in modifying the response of platelets could be observed in vivo.…”