Elsevier

Neuroscience Letters

Volume 309, Issue 3, 31 August 2001, Pages 165-168
Neuroscience Letters

Lowering glucose concentrations increases cytosolic Ca2+ in orexin neurons of the rat lateral hypothalamus

https://doi.org/10.1016/S0304-3940(01)02053-5Get rights and content

Abstract

Orexin neurons are specifically localized in and around the lateral hypothalamus (LH), a feeding center. Intracerebroventricular administration of orexin-A and -B stimulates feeding as well as arousal. However, little is known regarding the regulators of the orexin neuron activity. The neurons that are activated under low glucose conditions, glucose-sensitive neurons, are located in the LH and have been implicated in the control of feeding. The present study investigated the effect of glucose on the single orexin neurons isolated from the rat LH, by measuring cytosolic Ca2+ concentration ([Ca2+]i) by fura-2 microfluorometry followed by immunocytochemical staining with anti-orexin antiserum. A shift of glucose concentration form 8.3 to 2.8 mM in the superfusion solution increased [Ca2+]i in 13 out of 32 orexin-immunoreactive LH neurons. The results demonstrate that glucose-sensitive orexin neurons are present in the LH and that these neurons may play a role in linking the metabolic state in the body to the orexigenic, and could also, awakening signaling in the brain.

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Acknowledgements

This research was supported in part by grants from the Ministry of Education, Science, Sports and Culture of Japan (to T.Y.).

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