NO, CO, and H2 S: what about gasotransmitters in fish and amphibian heart?

The gasotransmitters nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H2 S), long considered only toxicant, are produced in vivo during the catabolism of common biological molecules, and are crucial for a large variety of physiological processes. Mounting evidence is emerging that in poikilotherm vertebrates, as in mammals, they modulate the basal performance of the heart and the response to stress challenges. In this review, we will focus on teleost fish and amphibians to highlight the evolutionary importance in vertebrates of the cardiac control elicited by NO, CO and H2 S, and the conservation of the intracellular cascades they activate. Although many gaps are still present due to discontinuous information, we will use examples obtained by studies from our and other laboratories to illustrate the complexity of the mechanisms that, by involving gasotransmitters, allows beat-to-beat, short-, medium- and long-term cardiac homeostasis. By presenting the latest data, we will also provide a framework in which the peculiar morpho-functional arrangement of the teleost and amphibian heart can be considered as a reference tool to decipher cardiac regulatory networks which are difficult to explore by using more conventional vertebrates, such as mammals. This article is protected by copyright. All rights reserved.