Isolation and Biological Activity of [Trp⁵]Bradykinin From the Plasma of the Phylogenetically Ancient Fish, the Bowfin and the Longnosed Gar

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• 作者：Conlon ; J. Michael ; Platzack ; Bjorn ; Marra ; Luciano E. ; Youson ; John H. ; Olson ; Kenneth R.
• 关键词：Bradykinin ; Holostean ; Arterial blood pressure
• 刊名：Peptides
• 出版年：1995
• 出版时间：1995
• 年：1995
• 卷：16
• 期：3
• 页码：485-489
• 全文大小：476 K

文摘

The holostean fish occupy an important position in vertebrate phylogeny as extant representatives of a ancient group of ray-finned fish with evolutionary connections to present-day teleosts. Incubation of heat-denatured plasma from the bowfinAmia calva with trypsin generated bradykinin-like immunoreactivity. The primary structure of bowfin bradykinin was established as Ala-Pro-Pro-Gly-Trp-Ser-Pro-Phe-Arg. This amino acid sequence contains one amino acid substitution (Phe⁵ → Trp) compared with mammalian bradykinin. The same peptide was generated in heat-denatured plasma from the longnosed gar Lepisosteus osseus. Treatment of plasma from either the bowfin or gar with glass beads under conditions previously shown to activate Factor XII in the plasma of mammals and reptiles did not generate bradykinin. Bolus injections of synthetic bowfin bradykinin (0.1, 0.3, and 1.0 nmol/kg) into the bulbus arteriosus of unanesthetized bowfin resulted in an immediate fall in arterial blood pressure of 5-10 min duration that was followed by a dose-dependent rise in pressure that was sustained for 30-60 min. There was no change in heart rate following bradykinin administration. The data suggest that the kallikrein-kinin system may predate the appearance of teleosts and may play a role in cardiovascular regulation in holosteans.