From molecule to behavior: hypocretin/orexin revisited from a sex-dependent perspective.

The hypocretin/orexin (Hcrt/Orx) system in the perifornical lateral hypothalamus has been recognized as a critical node in a complex network of neuronal systems controlling both physiology and behavior in vertebrates. Our understanding of the Hcrt/Orx system and its array of functions and actions have grown exponentially in merely two decades. This review will examine the latest progress in discerning the roles played by the Hcrt/Orx system in the regulation of homeostatic functions and in the execution of instinctive and learned behaviors. Furthermore, the gaps that currently exist in our knowledge of sex-related differences in this field of study are discussed.