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Animal migrations are of global ecological significance, providing mechanisms for the transport of nutrients and energy between distant locations. In much of the deep sea (>200 m water depth), the export of nutrients from the surface ocean provides a crucial but seasonally variable energy source to seafloor ecosystems. Seasonal faunal migrations have been hypothesized to occur on the deep seafloor as a result, but have not been documented. Here, we analyse a 7.5-year record of photographic data from the Deep-ocean Environmental Long-term Observatory Systems seafloor observatories to determine whether there was evidence of seasonal (intra-annual) migratory behaviours in a deep-sea fish assemblage on the West African margin and, if so, identify potential cues for the behaviour. Our findings demonstrate a correlation between intra-annual changes in demersal fish abundance at 1,400 m depth and satellite-derived estimates of primary production off the coast of Angola. Highest fish abundances were observed in late November with a smaller peak in June, occurring approximately 4 months after corresponding peaks in primary production. Observed changes in fish abundance occurred too rapidly to be explained by recruitment or mortality, and must therefore have a behavioural driver. Given the recurrent patterns observed, and the established importance of bottom-up trophic structuring in deep-sea ecosystems, we hypothesize that a large fraction of the fish assemblage may conduct seasonal migrations in this region, and propose seasonal variability in surface ocean primary production as a plausible cause. Such trophic control could lead to changes in the abundance of fishes across the seafloor by affecting secondary production of prey species and/or carrion availability for example. In summary, we present the first evidence for seasonally recurring patterns in deep-sea demersal fish abundances over a 7-year period, and demonstrate a previously unobserved level of dynamism in the deep sea, potentially mirroring the great migrations so well characterized in terrestrial systems., (© 2020 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.)

In rats, chronic administration of the nitric oxide (NO) inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) causes arterial hypertension, cardiac hypertrophy and myocardial ischemic alterations such as necrosis and fibrosis. In this study, we evaluated the effect of 8 weeks of treatment with enalapril maleate on cardiac weight and on the development of the histological alterations induced by L-NAME. Enalapril significantly inhibited the development of both arterial hypertension (117.2 +/- 5.8, 161.8 +/- 8.8 and 122.0 +/- 10.6 mm Hg, for control, L-NAME- and L-NAME + enalapril-treated animals, respectively) and left ventricular hypertrophy (1.36 +/- 0.13, 1.60 +/- 0.04 and 1.48 +/- 0.05 mg/g, for control, L-NAME- and L-NAME + enalapril-treated animals, respectively), but had no effect on the myocardial lesions. These findings demonstrate that although the renin-angiotensin system plays a major role in the development of arterial hypertension and cardiac hypertrophy, it does not modulate the ischemia-induced myocardial alterations observed in this model.