Faculty of Nursing

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Browsing Faculty of Nursing by Subject "appetite"

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    Effects of food deprivation and refeeding on neuropeptide Y (NPY) mRNA levels in goldfish
    (2001) Narnaware, Yuwaraj; Peter, Richard
    In mammals, NPY is a key factor in the regulation of feeding behavior. In the present study, the effects of refeeding for 1–3 h in 72–75-h food deprived (FD) goldfish on the levels of NPY mRNA in telencephalon-preoptic (TEL-POA), hypothalamus (HYP) and optic tectum-thalamus (OT-THAL) were examined, using Northern blot analysis. Goldfish FD for 72 h exhibited a significant increase in NPY mRNA levels in all brain regions. At 1 h after 72-h FD (73-h FD), NPY mRNA was significantly increased in TEL-POA and OT-THAL, but remained the same as 72-h FD fish in HYP. At 3 h after 72-h FD (75 h), all brain regions exhibited a significant increase in NPY mRNA levels. However, subsequent refeeding for 1–3 h rapidly and completely reversed the effects of FD in all brain regions, reaching fed levels within 1–3 h of refeeding. Serum GH levels were highest in 72-h FD fish, but decreased significantly over 1–3 h after 72-h FD; whereas, refeeding reversed the increase in serum GH levels only at 3 h after refeeding. Taken together, these results further support that NPY is a physiological brain transducer involved in the regulation of daily appetite and feeding in goldfish.
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    Influence of diet composition on food intake and neuropeptide Y (NPY) gene expression in goldfish brain
    (2002) Narnaware, Yuwaraj; Peter, Richard
    In this study, goldfish demonstrate preference for high carbohydrate and high fat diets, with no preference shown for high protein diets. Fish fed high (45% and 55%) carbohydrate (CHO) diets for 1 and 4 weeks exhibited decreased NPY gene expression in telencephalon–preoptic area (TEL–POA) and optic tectum–thalamus (OT–THAL) compared to fish fed low CHO (35% and 40%) diets. In hypothalamus (HYP), NPY gene expression was significantly increased after 1 week in fish fed both low and high CHO diets compared to control diet (40% CHO); after 4 weeks, the pattern in HYP was reversed. Fish fed a high fat (9%) diet had low NPY gene expression in TEL–POA after 1 and 4 weeks; however, HYP NPY expression was increased in fish fed a low (3%) fat diet after 1 week, and 2% and 3% fat diets after 4 weeks. In OT–THAL, NPY gene expression was decreased in fish fed a 2% fat diet for 1 week, and increased after 4 weeks. Feeding diets with different protein contents for 1 or 4 weeks did not influence NPY gene expression in goldfish brain. The results demonstrate, for the first time in a lower vertebrate, that NPY gene expression in goldfish brain is influenced by macronutrient intake.