Effects of fasting and feeding on the brain mRNA expressions of orexin, tyrosine hydroxylase (TH), PYY and CCK in the Mexican blind cavefish (Astyanax fasciatus mexicanus).

The effects of fasting and feeding on the brain expression of orexin (OX), tyrosine hydroxylase (TH), peptide Y (PY) and cholecystokinin (CCK) were examined in the blind cavefish Astyanax fasciatus mexicanus. A 10-days fasting period induced increases in both OX and TH brain mRNA expression but had no effect on PYY and CCK expression. Periprandial changes in expression were seen for OX, TH and PYY but not for CCK. OX brain expression peaked 1h prior to a scheduled meal and decreased 1h post feeding in fed fish. A peak in TH expression was seen 1h post feeding in unfed fish whereas a peak in PYY expression was seen 1h post feeding in fed fish. Our result indicates that brain OX, TH and PYY might be involved in the central regulation of feeding of blind cavefish.