The effect of sildenafil on the altered thoracic aorta smooth muscle responses in rat pre-eclampsia model.
The pathophysiology of pre-eclampsia is still unknown thus effective primary prevention is not possible at the stage. The present study was conducted to research the smooth muscle responses in the pre-eclampsia model with suramin treated rats and the effect of phosphodiesterase-5 (PDE5) inhibitor on these responses. Rats of three groups; control, suramin and suramin+sildenafil were given intraperitoneal injections of saline, suramin or sildenafil citrate. Suramin injections caused increased blood pressure, protein in urine and caused fetal growth retardation. The use of sildenafil citrate straightened significantly both blood pressure and average fetus weight, but did not reach to control values. At the end of pregnancy, thoracic aorta rings were exposed to contractile and relaxant agents. KCl contraction responses, sodium nitroprusside and papaverine relaxation responses were similar in three groups. Contraction responses of phenylephrine, increased significantly in suramin group. Relaxation responses of acethylcholine and bradykinin decreased in suramin group. The use of sildenafil citrate partially straightened both relaxation and contraction responses, but did not reach to control values. In all groups in the presence of L-nitromonomethylarginine (L-NAME), 1H-(1, 2, 4) oxadiazole (4, 3-a) guinoxalin-1-one (ODQ) and indomethacin decreased the relaxation responses of acetylcholine and bradykinin. The cyclic guanosine monophosphate (cGMP) content of thoracic aorta tissue was determined by radioimmunoassay technique. The content of cGMP in suramin group decreased and use of sildenafil citrate increased the cGMP content but did not reach to control values. We conclude that in pre-eclampsia, the increase of contraction responses, the decrease of relaxation responses and the decrease of cGMP content can depend on insufficiency about synthesis or release of relaxant factors which was released from the vessel endothelium. The results in this study show that in pre-eclampsia; PDE5 inhibitors enhance endothelial function and may be used for protection. Further studies are needed to clear the efficiency and safety of PDE5 inhibitors.
Department of Pharmacology, Institute of Health Sciences, Cumhuriyet University, Sivas, Turkey. nergizht@yahoo.com <nergizht@yahoo.com>
Nergiz Hacer
NH
Turgut
Tijen Kaya
TK
Temiz
Ihsan
I
Bagcivan
Bulent
B
Turgut
Sefa
S
Gulturk
Baris
B
Karadas
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000503:physiopathology; D001794:Blood Pressure / Q000187:drug effects; D006152:Cyclic GMP / Q000378:metabolism; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5 / Q000378:metabolism; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D047109:Fetal Development / Q000187:drug effects; D005317:Fetal Growth Retardation / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000201:enzymology / Q000503:physiopathology; D058986:Phosphodiesterase 5 Inhibitors; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology*; D011225:Pre-Eclampsia / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D011247:Pregnancy; D011507:Proteinuria / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology; D011687:Purines / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000494:pharmacology*; D013498:Suramin; D014661:Vasoconstriction / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
D058986:Phosphodiesterase 5 Inhibitors; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D013498:Suramin; D000068677:Sildenafil Citrate; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D006152:Cyclic GMP