BETA-ADRENERGIC-RECEPTOR STIMULATED PROSTACYCLIN SYNTHESIS IN RABBIT CORONARY ENDOTHELIAL-CELLS IS MEDIATED BY SELECTIVE ACTIVATION OF PHOSPHOLIPASE-D - INHIBITION BY ADENOSINE 3'5'-CYCLIC MONOPHOSPHATE
Y. Ruan et al., BETA-ADRENERGIC-RECEPTOR STIMULATED PROSTACYCLIN SYNTHESIS IN RABBIT CORONARY ENDOTHELIAL-CELLS IS MEDIATED BY SELECTIVE ACTIVATION OF PHOSPHOLIPASE-D - INHIBITION BY ADENOSINE 3'5'-CYCLIC MONOPHOSPHATE, The Journal of pharmacology and experimental therapeutics, 281(3), 1997, pp. 1038-1046
Activation of beta adrenergic receptors in the isolated rabbit heart b
y catecholamines stimulates prostacyclin (PGI(2)) synthesis, which is
inhibited by adenosine 3'5'-cyclic monophosphate (cAMP). The purpose o
f this study was to determine if activation of beta adrenergic recepto
rs in cultured coronary endothelial cells (CEC) of rabbit heart with i
soproterenol (ISOP) stimulates PGI(2) synthesis and if cAMP inhibits t
he synthesis of this prostanoid and to investigate the underlying mech
anism. Incubation of CEC with ISOP increased production of cAMP and PG
I(2), measured as immunoreactive cAMP and 6-keto-prostaglandin F-1 alp
ha, (6-keto-PGF(1 alpha)), respectively. Forskolin, an activator of ad
enylyl cyclase, increased cAMP accumulation and inhibited ISOP-stimula
ted 6-keto-PGF(1 alpha) synthesis, 8-(4-chlorophenylthio) cAMP also in
hibited ISOP-induced 6-keto-PGF(1 alpha) production. However, miconazo
le, an inhibitor of adenylyl cyclase, reduced cAMP accumulation and en
hanced ISOP-stimulated 6-keto-PGF(1 alpha) synthesis in CEC. ISOP-indu
ced 6-keto-PGF(1 alpha) synthesis was attenuated by C-2-ceramide, an i
nhibitor of phospholipase D (PLD) by propranolol, a beta-AR antagonist
that also inhibits phosphatidate phosphohydrolase and by the diacylgl
ycerol lipase inhibitor 1,6-bis-(cyclohexyloximinocarbonylamino)-hexan
e (RHC 80267), Acetylcholine (ACh) induced 6-keto-PGF(1 alpha) synthes
is was also inhibited by these agents. Both ISOP and ACh increased PLD
activity, which was inhibited by C-2-ceramide but not by RHC 80267 or
propranolol. ACh but not ISOP increased phospholipase A(2) activity i
n CEC, ISOP- but not ACh-induced increase in PLD activity was attenuat
ed by forskolin and 8-(4-chlorophenyl-thio)-adenosine 3'-5'-cyclic mon
ophosphate and augmented by miconazole. These data suggest that beta a
drenergic receptors activation promotes PGI(2) synthesis in the CEC by
selective activation of PLD and that cAMP decreases PGI(2) synthesis
by decreasing PLD activity. Moreover, beta adrenergic receptors activa
ted PLD appears to be distinct from that stimulated by ACh.