Nitric oxide-mediated arachidonic acid release from perifused Venus verrucosa oocytes.
This study was undertaken in order to investigate the possible interactions between nitric oxide and arachidonic acid (AA) in Venus verrucosa oocytes. We perifused isolated oocytes to determine the effect of the following substances on [3H]arachidonic acid release ([3H]AA): (1) A 23187, a calcium ionophore; (2) nitric oxide (NO) donors; (3) 1,1,1-trifluoromethyl-6,9,12,15 heicosatetraen-2-one (AACOCF(3)), a specific phospholipase A(2) (PLA(2)) inhibitor; (4) [5'-hydroxymethyl-2'-furyl]-1-benzyl indazole (YC-1) and 1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one (ODQ), specific soluble guanylyl cyclase activator and inhibitor, respectively; (5) L-arginine, the substrate of nitric oxide synthase; (6) L-nitroarginine methyl esther (L-NAME), an inhibitor of nitric oxide synthase. Our results demonstrated that: (a) the calcium ionophore dose-dependently increased [3H]arachidonic acid release; (b) the NO donors sodium nitroprusside (SNP) and linsidomine (SIN-1) highly increased [3H]arachidonic acid output, while S-nitroso-N-acetylpenicillamine (SNAP) was without effect; (c) AACOCF(3) completely blocked the [3H]arachidonic acid release induced by SNP and SIN-1; (d) YC-1 increased [3H]arachidonic acid release, while ODQ completely counteracted SNP response; (e) [3H]arachidonic acid output was also increased by L-arginine; (f) a similar effect was, paradoxically, obtained in the presence of L-NAME. Furthermore, using RT-PCR we demonstrated in the same cells the presence of a nitric oxide synthase (NOS) mRNA, whose expression was not modulated by interleukin 1beta (IL-1beta). These results demonstrate the presence of a both calcium-dependent and NO-sensitive PLA(2) and of nitric oxide synthase in V. verrucosa oocytes. Our data also suggest a co-action of the two pathways in the control of reproduction in this bivalve.
Barbin
Laura
L
Department of Biology, General Physiology Section, University of Ferrara, via Luigi Borsari, 46, Ferrara I-44100, Italy.
Boarini
Isabella
I
Borasio
Pier Giorgio
PG
Barion
Paola
P
Fiorini
Sara
S
Rossi
Remigio
R
Biondi
Carla
C
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D049872:Bivalvia / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D066298:In Vitro Techniques; D008563:Membrane Lipids / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism; D012098:Reproduction / Q000502:physiology
D008563:Membrane Lipids; D020030:Nitric Oxide Donors; D016718:Arachidonic Acid; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D010741:Phospholipases A; D002118:Calcium