Abstract
Orexin A and B are a pair of neuropeptides implicated in the regulation of sleep/wakefulness and energy homeostasis. The regulatory mechanism of orexin neurons is poorly understood since the small number of orexin neurons is sparsely distributed in the lateral hypothalamus. We made the following transgenic (Tg) mice to study the physiological role in the regulation of sleep/wakefulness.Orexin/cameleon Tg mice, in which orexin neurons specifically express calcium sensing protein, were used for calcium imaging to screen what kind of neurotransmitter affects the activity of orexin neurons.Orexin/EGFP Tg mice, in which orexin neurons express EGFP, were used for electrophysiological studies to reveal intracellular mechanisms involved in the activation or inhibition response. Orexin/GFP::TTC Tg mice, in which orexin neurons express a retrograde tracer, were used for immunohistochemical studies to reveal which neurons directly innervate orexin neurons. These studies using Tg mice revealed how orexin neurons are regulated by afferent neurons. [J Physiol Sci. 2006;56 Suppl:S37]
