title: Vasorelaxant activity of cyclic peptide, cyclosquamosin B, from Annona squamosa.
abstract: A cyclic octapeptide, cyclosquamosin B (2), isolated from the seeds of Annona squamosa showed a vasorelaxant effect on rat aorta. It showed a slow relaxation activity against norepinephrine (NE)-induced contractions of rat aorta with/without endothelium. It showed inhibition effect on vasocontraction of depolarized aorta with high concentration potassium, but moderately inhibition effect on NE-induced contraction in the presence of nicardipine. These results showed that the vasorelaxant effect by 2 might be attributed mainly to inhibition of calcium influx from extracellular space through voltage-dependent calcium channels.
authors.affiliation: Faculty of Pharmaceutical Sciences, Hoshi University, Shinagawa-ku, Tokyo, Japan. moritah@hoshi.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Morita
authors.forename: Toru
authors.initials: T
authors.lastname: Iizuka
authors.forename: Chee-Yan
authors.initials: CY
authors.lastname: Choo
authors.forename: Kit-Lam
authors.initials: KL
authors.lastname: Chan
authors.forename: Koichi
authors.initials: K
authors.lastname: Takeya
authors.forename: Jun'ichi
authors.initials: J
authors.lastname: Kobayashi
mesh_terms: D000818:Animals; D031041:Annona / Q000737:chemistry*; D001011:Aorta / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology; D015394:Molecular Structure; D010456:Peptides, Cyclic / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D051381:Rats; D012639:Seeds / Q000737:chemistry; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D010456:Peptides, Cyclic; D010936:Plant Extracts; C514049:cyclosquamosin B; D002118:Calcium