title: Evidence for nonadrenoceptor responses to imidazoline derivatives in the porcine isolated rectal artery.
abstract: High concentrations of phentolamine, efaroxan, and idazoxan were found to produce nonadrenoceptor contractions of the porcine isolated rectal artery previously exposed to U46619 and forskolin. These responses were insensitive to the putative imidazoline I(3) receptor antagonist KU-14R, unlike those previously reported in this preparation for oxymetazoline. The pharmacologic nature of this response and the obligate requirement for preconstriction suggests that these imidazoline derivatives modulate ion channel function through a novel nonadrenergic site.
authors.affiliation: School of Biomedical Sciences, University of Nottingham, Nottingham, UK.
authors.forename: Minyan
authors.initials: M
authors.lastname: Wang
authors.forename: W R
authors.initials: WR
authors.lastname: Dunn
authors.forename: S L
authors.initials: SL
authors.lastname: Chan
authors.forename: B
authors.initials: B
authors.lastname: Garfield
authors.forename: V G
authors.initials: VG
authors.lastname: Wilson
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D001158:Arteries / Q000033:anatomy & histology / Q000378:metabolism*; D001572:Benzofurans / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D007093:Imidazoles / Q000737:chemistry / Q000494:pharmacology*; D054755:Imidazoline Receptors; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D010643:Phenoxybenzamine / Q000494:pharmacology; D011955:Receptors, Drug / Q000378:metabolism; D012007:Rectum / Q000098:blood supply*; D013552:Swine; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: D000317:Adrenergic alpha-Antagonists; D001572:Benzofurans; D007093:Imidazoles; D054755:Imidazoline Receptors; C106086:KU 14R; D011955:Receptors, Drug; D014662:Vasoconstrictor Agents; D010643:Phenoxybenzamine; D005576:Colforsin; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid