Modulation by adenosine of thromboxane A2 receptor-mediated constriction in the human umbilical artery.
The powerful vasoconstrictor autacoid thromboxane A2 (TxA2) has pathological roles in many diseases including pre-eclampsia or pregnancy induced hypertension (PIH). Adenosine and other purines are released by tissues during ischemia as occurs in the utero-placental circulation during PIH. These substances, particularly adenosine, may modulate TxA2 constrictor responses. We therefore characterized TxA2 receptors in the umbilical artery in vitro using the competitive antagonist GR32191. Also examined was the Ca2+ channels' involvement in adenosine-induced inhibition of TxA2 vasoconstriction. Results showed that TxA2 receptors on umbilical arteries are identical to those present in platelets, the placenta and umbilical vein. Adenosine was found to inhibit equally constriction involving either voltage or receptor operated Ca2+ channels.
Istituto di Clinica Medica L. Condorelli, Università di Catania, Italy.
A
A
Di Grande
L S
LS
Malatino
A L
AL
Boura
M A
MA
Read
W A
WA
Walters
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000241:Adenosine / Q000494:pharmacology*; D000293:Adolescent; D000328:Adult; D001713:Biphenyl Compounds / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects; D004347:Drug Interactions; D005260:Female; D006538:Heptanoic Acids / Q000494:pharmacology; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009543:Nifedipine / Q000494:pharmacology; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology; D017482:Receptors, Thromboxane / Q000037:antagonists & inhibitors* / Q000187:drug effects; D013928:Thromboxane A2 / Q000031:analogs & derivatives / Q000494:pharmacology; D014469:Umbilical Arteries / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D001713:Biphenyl Compounds; D015220:Calcium Channels; D006538:Heptanoic Acids; D011450:Prostaglandin Endoperoxides, Synthetic; D017482:Receptors, Thromboxane; D014662:Vasoconstrictor Agents; D013928:Thromboxane A2; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; C060013:vapiprost; D009543:Nifedipine; D000241:Adenosine