Effect of a nitric oxide releasing compound isosorbide dinitrate on development and cardiovascular physiology of rainbow trout (Oncorhynchus mykiss)

Rainbow trout (Oncorhynchus mykiss) eggs and alevins were exposed for up to 4 weeks to the nitricoxide (NO) donor isosorbide dinitrate (ISDN) at conce ntrations up to 100 mu mol l(-1). Hatching success was over 95%, but increa sing concentrations of ISDN significantly delayed hatching, without signifi cant affects on survival. Alevins exposed to ISDN concentrations of 50 or 1 00 mu mol l(-1) showed significant cardiovascular and developmental changes compared to unexposed alevins. These included lowered heart rate and venti lation rate, doubling of cardiac output, dilation of the vitelline vein and increased in alevin weight. The results indicate a vasodilatory role of NO in trout alevins, and their cardiovascular responses to NO, with reference to the role of the vitelline vein, are discussed.