Immunoreactivity of hypothalamic orexin-containing neurons in rats in movement restriction and cooling

Studies of the immunoreactivity of hypothalamic orexin-containing neurons during the development of the brain's response to movement restriction and cooling in rats demonstrated selective changes in the immunoreactivity of orexin-containing neurons during these treatments; in particular, orexin-containing neurons located in structures on brain sections at levels 28, 29, and 31 responded with different changes in immunoreactivity, providing evidence of the specialization and functional heterogeneity of the hypothalamic orexin-containing neuron population. We provide the first identification of the hypothalamic structures and zones including orexin-containing neurons involved in the development of the set of reactions occurring in the brain during the formation of responses to stressors. Changes in the immunoreactivity of orexin-containing neurons located in areas involved in the systems regulating heat production (DMH, PH, and some zones of the LHA) provide grounds for suggesting that orexin-containing neurons may be involved in thermoregulatory processes. © 2011 Springer Science+Business Media, Inc.