Cardiovascular effects of homologous bradykinin in rainbow trout

Kenneth Olson, Daniel J. Conklin

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Bradykinins have only recently been identified in fish, and a detailed analysis of their cardiovascular actions is lacking. The present study examines the cardiovascular effects of trout bradykinin ([Arg°)Trp5,Leu8]bradykinin; tBK) in conscious trout, Oncorhynchus mykiss. tBK (1-10 nmol/kg body wt bolus) produced triphasic pressor-depressor-pressor responses. Inphase 1, cardiac output (CO), ventral aortic (PVA), dorsal aortic (PDA), and central venous pressure increased, whereas systemic (Rs) and gill resistance (RG) were unchanged. Inphase 2, RG increased, whereas Rs, CO, and heart rate decreased, reducing PVA and PDA. Plasma prostaglandin E2 and the prostacyclin metabolite, 6-ketoprostaglandin Fla, were significantly elevated duringp/iase 2, whereas leukotrienes C4 and B4 and thromboxane B2 were unaffected. Phase 3 was produced by an increased CO and RS and the return of RG to control. Phase 1 pressor response was not blocked by inhibitors of cyclooxygenase, angiotensin-converting enzyme (ACE) or α-adrenoceptors (α-AD), whereas phase 2 depressor and plasma prostaglandin responses were prevented by cyclooxygenase inhibition. Phase 3 was partially blocked by ACE and α-AD inhibitors and is a response to the preceding hypotension. In vitro, tBK only decreased vascular resistance in the perfused splanchnic or skeletal muscle-kidney preparations, These results show that although tBK has multiple effects on the trout cardiovascular system, none of the effects are due to direct tBK stimulation of vascular smooth muscle. Phase 2 vasodilation has features consistent with release of vasodilator prostaglandins while the mechanism of phase 1 constriction is unknown.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume41
Issue number4
StatePublished - 1997

Fingerprint

Trout
Oncorhynchus mykiss
Bradykinin
Cardiac Output
Angiotensin-Converting Enzyme Inhibitors
Prostaglandins
Leukotriene C4
Thromboxane B2
Central Venous Pressure
Leukotriene B4
Viscera
Epoprostenol
Prostaglandin-Endoperoxide Synthases
Cardiovascular System
Vasodilator Agents
Vascular Smooth Muscle
Dinoprostone
Constriction
Vasodilation
Vascular Resistance

Keywords

  • Endothelium-derived relaxing factor
  • Kallikrein-kinin system
  • Prostaglandins

ASJC Scopus subject areas

  • Physiology

Cite this

Cardiovascular effects of homologous bradykinin in rainbow trout. / Olson, Kenneth; Conklin, Daniel J.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 41, No. 4, 1997.

Research output: Contribution to journalArticle

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