title: Agonism at 5-HT2B receptors is not a class effect of the ergolines.
abstract: Restrictive cardiac valvulopathies observed in Parkinson patients treated with the ergoline dopamine agonist pergolide have recently been associated with the agonist efficacy of the drug at 5-hydroxytryptamine2B (5-HT2B) receptors. To evaluate whether agonism at 5-HT2B receptors is a phenomenon of the class of the ergolines, we studied 5-HT2B receptor-mediated relaxation in porcine pulmonary arteries to five ergolines which are used as antiparkinsonian drugs. Pergolide and cabergoline were potent full agonists in this tissue (pEC50 8.42 and 8.72). Bromocriptine acted as a partial agonist (pEC50 6.86). Lisuride and terguride, however, failed to relax the arteries but potently antagonized 5-HT-induced relaxation (pKB 10.32 and 8.49). Thus, agonism at 5-HT2B receptors seems not to be a class effect of the ergolines.
authors.affiliation: Free University of Berlin, Institute of Pharmacy, Königin-Luise-Str. 2+4, 14195 Berlin, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Jähnichen
authors.forename: Reinhard
authors.initials: R
authors.lastname: Horowski
authors.forename: Heinz H
authors.initials: HH
authors.lastname: Pertz
mesh_terms: D000818:Animals; D000978:Antiparkinson Agents / Q000737:chemistry / Q000494:pharmacology*; D015237:Dinoprost / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000378:metabolism; D004873:Ergolines / Q000737:chemistry / Q000494:pharmacology*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D011651:Pulmonary Artery / Q000187:drug effects / Q000502:physiology; D058826:Serotonin 5-HT2 Receptor Agonists; D058830:Serotonin 5-HT2 Receptor Antagonists; D013329:Structure-Activity Relationship; D013552:Swine; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: D000978:Antiparkinson Agents; D004873:Ergolines; D058826:Serotonin 5-HT2 Receptor Agonists; D058830:Serotonin 5-HT2 Receptor Antagonists; D014662:Vasoconstrictor Agents; D015237:Dinoprost