title: Recombinant interleukin-1β dilates steelhead trout coronary microvessels: effect of temperature and role of the endothelium, nitric oxide and prostaglandins.
abstract: Interleukin (IL)-1β is associated with hypotension and cardiovascular collapse in mammals during heat stroke, and the mRNA expression of this pro-inflammatory cytokine increases dramatically in the blood of Atlantic cod (Gadus morhua) at high temperatures. These data suggest that release of IL-1β at high temperatures negatively impacts fish cardiovascular function and could be a primary determinant of upper thermal tolerance in this taxa. Thus, we measured the concentration-dependent response of isolated steelhead trout (Oncorhynchus mykiss) coronary microvessels (<150 μm in diameter) to recombinant (r) IL-1β at two temperatures (10 and 20°C). Recombinant IL-1β induced a concentration-dependent vasodilation with vessel diameter increasing by approximately 8 and 30% at 10(-8) and 10(-7) mol l(-1), respectively. However, this effect was not temperature dependent. Both vessel denudation and cyclooxygenase blockade (by indomethacin), but not the nitric oxide (NO) antagonist L-NIO, inhibited the vasodilator effect of rIL-1β. In contrast, the concentration-dependent dilation caused by the endothelium-dependent calcium ionophore A23187 was completely abolished by L-NIO and indomethacin, suggesting that both NO and prostaglandin signaling mechanisms exist in the trout coronary microvasculature. These data: (1) are the first to demonstrate a functional link between the immune and cardiovascular systems in fishes; (2) suggest that IL-1β release at high temperatures may reduce systemic vascular resistance, and thus, the capacity of fish to maintain blood pressure; and (3) provide evidence that both NO and prostaglandins play a role in regulating coronary vascular tone, and thus, blood flow.
authors.affiliation: Department of Ocean Sciences, Memorial University of Newfoundland, St. John's, NL, Canada A1C 5S7.
authors.forename: Isabel A S F
authors.initials: IA
authors.lastname: Costa
authors.affiliation: Department of Surgery, College of Medicine, Texas A&M Health Science Center, Baylor Scott & White Health, Temple, TX 76508, USA.
authors.forename: Travis W
authors.initials: TW
authors.lastname: Hein
authors.affiliation: School of Biological Sciences, Scottish Fish Immunology Research Centre, University of Aberdeen, Aberdeen AB24 2TZ, UK.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Secombes
authors.affiliation: Department of Ocean Sciences, Memorial University of Newfoundland, St. John's, NL, Canada A1C 5S7 kgamperl@mun.ca.
authors.forename: A Kurt
authors.initials: AK
authors.lastname: Gamperl
mesh_terms: D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D061207:Calcium Ionophores / Q000494:pharmacology; D003331:Coronary Vessels / Q000187:drug effects* / Q000502:physiology*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D053583:Interleukin-1beta / Q000494:pharmacology*; D055806:Microvessels / Q000187:drug effects / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D017686:Oncorhynchus mykiss / Q000502:physiology*; D009952:Ornithine / Q000031:analogs & derivatives / Q000494:pharmacology; D011453:Prostaglandins / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D013696:Temperature; D014664:Vasodilation / Q000502:physiology*
chemical_list: D061207:Calcium Ionophores; D016861:Cyclooxygenase Inhibitors; D053583:Interleukin-1beta; D011453:Prostaglandins; D011994:Recombinant Proteins; D009569:Nitric Oxide; C065027:N(G)-iminoethylornithine; D000001:Calcimycin; D009952:Ornithine; D019001:Nitric Oxide Synthase; D007213:Indomethacin
keywords: Cytokine; Heart; Oncorhynchus mykiss; Tone; Vascular resistance; Vasomotor responses