title: Direct vasoconstrictor action of homologous angiotensin II on isolated arterial ring preparations in an elasmobranch fish.
abstract: Arterial rings were prepared from the branchial artery, coeliac artery and ventral aorta of the Japanese dogfish Triakis scyllia and used to determine arterial contraction in a myograph. Noradrenaline caused a dose-dependent contraction (10(-9)-3 x 10(-6) M) that was completely inhibited by pre-treatment with 10(-7) M phentolamine. Homologous dogfish angiotensin II (ANG II) ([Asn1, Pro3, Ile5]-ANG II) also caused dose-dependent contraction (10(-9)-3 x 10(-6) M), but phentolamine had no effect on this response. Administration of dogfish angiotensin I (ANG-I) ([Asn1, Pro3, Ile5, Gln9]-ANG I) resulted in a contraction similar to that produced by ANG II and the effect could be blocked with 10(-7) M captopril. The mammalian ANG II receptor antagonists [Sar1, Ile8]-ANG II and [Sar1, Ala8]-ANG II caused dose-dependent contractions of coeliac artery rings, but were less potent than homologous ANG I and ANG II. These results show that the contractile effect of [Asn1, Pro3, Ile5]-ANG II is not mediated by the alpha-adrenergic system and contractions of arterial rings by noradrenaline and elasmobranch ANG II are mediated by separate vascular receptors. The elasmobranch ANG II vascular receptor may have co-evolved with the unusual structure of this peptide.
authors.affiliation: National Research Institute of Fisheries Science, Yokohama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Hamano
authors.forename: M L
authors.initials: ML
authors.lastname: Tierney
authors.forename: K
authors.initials: K
authors.lastname: Ashida
authors.forename: Y
authors.initials: Y
authors.lastname: Takei
authors.forename: N
authors.initials: N
authors.lastname: Hazon
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000803:Angiotensin I / Q000494:pharmacology; D000804:Angiotensin II / Q000031:analogs & derivatives / Q000494:pharmacology*; D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D001011:Aorta; D001808:Blood Vessels / Q000187:drug effects*; D001916:Brachial Artery; D002216:Captopril / Q000494:pharmacology; D002445:Celiac Artery; D004284:Dogfish / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D008322:Mammals; D009638:Norepinephrine / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011945:Receptors, Angiotensin / Q000378:metabolism*; D012504:Saralasin; D014661:Vasoconstriction
chemical_list: D000317:Adrenergic alpha-Antagonists; D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D004791:Enzyme Inhibitors; D011945:Receptors, Angiotensin; D000804:Angiotensin II; C032651:angiotensin II, Sar(1)-Ile(5)-; D000803:Angiotensin I; D002216:Captopril; D012504:Saralasin; D009638:Norepinephrine; D010646:Phentolamine