Diurnal modulations of neuropeptides ‘cocaine- and amphetamine- regulated transcript’ and ‘Neuropeptide Y’ in the brain of <i>E. cyanophlyctis</i>

Cocaine- and amphetamine- regulated transcript (CART) and Neuropeptide Y (NPY) primarily regulate energy homeostasis. Anurans exhibit diurnal behavioral rhythm, but the response of central neuropeptides to the Day-Night cycle is not elucidated. In this study, we have examined the profile of CART and NPY in the brain of Euphlyctis cyanophlyctis from 6:00 h to 24:00 h. Although expressions of CART and NPY changed with time of the day, circadian oscillation was observed only in expression of CART in anteroventral tegmentum (AV). CART exhibited a single peak in preoptic area (POA), Edinger-Westphal nucleus (EW), nucleus isthmus (NI) and raphe nucleus (Ra); two peaks in ventral hypothamalus (vHy), habenula (Hb) and torus semicircularis (TS). NPY exhibited single peak in TS and suprachiasmatic nucleus (SCN); two peaks in POA, vHy, AV and EW. The daily modulations of these neuropeptides may contribute to their physiological activities and are evolutionarily conserved.