Orexin receptor type 1
The 425 amino acid orexin receptor type 1 is coded by the HCRTR1 gene at 1p33. It is a moderately selective excitatory receptor for orexin-A and has lower affinity for orexin-B. In embyonic renal cells it stimulation increases glucose uptake with higher glycolytic activity, favouring ATP production through the tricarboxylic acid cycle and oxidative phosphorylation. Orexin receptor antagonists when used for sleep regulation may block it causing side effects on appetite, autonomic function, hormonal balance and the regulation of fluid balance.