Drinking rate in juvenile Atlantic salmon,Salmo salar L fry in response to a nitric oxide donor, sodium nitroprusside and an inhibitor of angiotensin converting enzyme, enalapril
- Cite this article as:
- Fuentes, J., McGeer, J.C. & Eddy, F.B. Fish Physiol Biochem (1996) 15: 65. doi:10.1007/BF01874839
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Drinking in freshwater juvenile salmon was investigated in response to vasodilation by sodium nitroprusside (SNP), a nitric oxide donor, which significantly increased blood vessel diameter in Atlantic salmon alevins. Atlantic salmon fry (1–3 g), as previously shown, drank at a significant rate in fresh water which doubled to about 1.2 ml kg−1 h−1 following injection of SNP (100 μmol kg−1), through dilation of body vasculature and activation of a vasoconstrictive mechanism, the endogenous renin angiotensin system (RAS). This response was 50% inhibited by injection of about 100 mg kg−1 enalapril. Fry increased drinking in response to SNP administered in the water, though the concentration required for maximal response, 1.6 mmol l−1, was much greater than for injected SNP; this response was also inhibited by enalapril injection. Possible involvement of the gill vasculature and branchial osmoreceptors or baroreceptors in control of the drinking response is discussed.