Hypocretin (orexin) immunoreactivity in the feline midbrain: Relevance for the generation of wakefulness.

Journal of Chemical Neuroanatomy
Alicia CostaPablo Torterolo

Abstract

Hypocretins (Hcrt) 1 and 2 are two neuropeptides synthesized from neurons that are located in the perifornical area of the lateral hypothalamus. These neurons project diffusely throughout the central nervous system, and have been implicated in the generation and maintenance of wakefulness, as well as in critical physiological processes that occur during this behavioral state, such as motivation. The hypocretinergic projections towards the feline midbrain have not been studied before. Therefore, the aim of the present study was to analyze their relationship to the midbrain neurons, that are critically involved in the control of sleep and wakefulness. With this purpose, we examined the distribution of Hcrt1-positive fibers in the midbrain and pontomesencephalic area of the domestic cat (Felis catus), and their relationship with catecholaminergic and cholinergic neurons by means of single and double immunohistochemistry. Hcrtergic axons with distinctive varicosities and buttons were heterogeneously distributed, exhibiting different densities in distinct regions of the midbrain. High Hcrtergic fiber densities were observed in the periaqueductal gray, interpeduncular nucleus, locus coeruleus and cholinergic mesopontine regions. In a...Continue Reading

Citations

Jul 6, 2021·Metabolic Brain Disease·Idris A AzeezJames O Olopade

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