Hypotensive and regional hemodynamic effects of the dopamine receptor agonist SK & F 85174 in the anesthetized rat.
The effects of the D1/D2 dopamine receptor agonist SK & F 85174, an N-allyl derivative of fenoldopam, on blood pressure and regional hemodynamics were studied in anesthetized normotensive rats. SK & F 85174 reduced blood pressure and enhanced blood flow in the renal, superior mesenteric and the hindquarters vascular beds. Calculated vascular resistances were reduced. The nonselective dopamine receptor antagonist RS-sulpiride abolished, while SCH 23390 (D1 antagonist), domperidone (D2 antagonist) and hexamethonium (ganglion blocker) each partly blocked the hypotensive effect. SCH 23390 antagonized the vasodilator effect more in the renal and superior mesenteric vascular beds, whereas domperidone antagonized the response more in the hindquarters vascular bed. RS-sulpiride antagonized vasodilatation in the three vascular beds. Hexamethonium abolished vasodilatation in the hindquarters vascular bed only. These results indicate that the hypotensive effect of SK & F 85174 is due to stimulation of both postsynaptic D1 and neuronal D2 receptors. The vasodilator effect in the renal and superior mesenteric vascular beds is mediated by D1 receptor stimulation, the vasodilator response in the hindquarters vascular bed is due to neuronal D2 receptor stimulation.
Department of Pharmacology, Free University of Brussels, Belgium.
P
P
Van der Niepen
D F
DF
Schoors
A G
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Dupont
D000818:Animals; D001552:Benzazepines / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D015259:Dopamine Agents / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D012039:Regional Blood Flow / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D001552:Benzazepines; D015259:Dopamine Agents; C045977:SK&F 85174