Absence of Nitrergic Modulation of Starling Response in Haemoglobin-Less Antarctic Fish Chionodraco hamatus

The Frank-Starling response is an intrinsic heart property that particularly evident in the fish because piscine cardiomyocytes are extremely sensitive to stretch. Several mechanisms and compounds influence response, including free radical nitric oxide produced by synthases vascular endothelium of all vertebrates. Besides its role scavenging oxide, hemoglobin may act as a source transporter. In this context, hemoglobin-less Antarctic teleost Chionodraco hamatus (icefish) represents unique opportunity investigate involvement response. Using isolated perfused preparation, weverified basal nitrergic tone not implicated addition, comparing expression activation C. red-blooded Trematomus bernacchii, we found endothelial isoform synthase (the primary generator during shear stress) be less expressed activated former.