| Scientists at the University of Cambridge compared actions of different nutrients on orexin cells. |
| For example, physical activity increased in rats when injected with orexin, a brain chemical associated with sexual arousal. |
| Belsomra is an orexin receptor antagonist and is the first approved drug of this type. |
| The scientists also found that the orexin neurons in the brains of injured mice were much less active than the same neurons in uninjured mice. |
| Human narcolepsy generally stems from a shortage of the neurons, which produce the excitatory neurotransmitter known both as hypocretin and orexin. |
| Increased production of orexin A and MCH, which are both orexigenic peptides, may explain the increased food intake observed in HP mice. |
