Excitatory action of hypocretin/orexin on neurons of the central medial amygdala

• Published in: Neuroscience 2006-11, Vol.142 (4), p.999-1004
• Main Authors: Bisetti, A., Cvetkovic, V., Serafin, M., Bayer, L., Machard, D., Jones, B.E., Mühlethaler, M.
• Format: Article
• Language: English
• Subjects: Action Potentials; Action Potentials - drug effects; Action Potentials - physiology; Amygdala; Amygdala - drug effects; Amygdala - metabolism; Animals; Arousal; Arousal - drug effects; Arousal - physiology; Biological and medical sciences; Excitatory Postsynaptic Potentials; Excitatory Postsynaptic Potentials - drug effects; Excitatory Postsynaptic Potentials - physiology; Fear; Fear - drug effects; Fear - physiology; Fundamental and applied biological sciences. Psychology; hypothalamus; Intracellular Signaling Peptides and Proteins; Intracellular Signaling Peptides and Proteins - metabolism; Intracellular Signaling Peptides and Proteins - pharmacology; Life Sciences; Neural Pathways; Neural Pathways - drug effects; Neural Pathways - metabolism; Neurobiology; Neurons; Neurons - drug effects; Neurons - metabolism; Neurons and Cognition; Neuropeptides; Neuropeptides - metabolism; Neuropeptides - pharmacology; Orexin Receptors; Orexins; Organ Culture Techniques; peptide; Potassium Channels; Potassium Channels - drug effects; Potassium Channels - metabolism; Rats; Receptors, G-Protein-Coupled; Receptors, G-Protein-Coupled - drug effects; Receptors, G-Protein-Coupled - metabolism; Receptors, Neuropeptide; Receptors, Neuropeptide - drug effects; Receptors, Neuropeptide - metabolism; Receptors, Vasopressin; Receptors, Vasopressin - agonists; Receptors, Vasopressin - metabolism; sleep; Sleep. Vigilance; stress; Stress, Psychological; Stress, Psychological - metabolism; Stress, Psychological - physiopathology; Synaptic Transmission; Synaptic Transmission - drug effects; Synaptic Transmission - physiology; Vasopressins; Vasopressins - metabolism; Vasopressins - pharmacology; Vertebrates: nervous system and sense organs; wakefulness
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2006.07.018

The neurons of the lateral hypothalamus that contain hypocretin/orexin (hcrt/orx) are thought to promote arousal through the excitatory action they exert on the multiple areas to which they project within the CNS. We show here that the hcrt/orx peptides can also exert a strong action on the amygdala, a structure known for its implication in emotional aspects of behavior. Indeed, the hcrt/orx peptides, applied in acute rat brain slices, excite a specific class of “low threshold burst” neurons in the central medial (CeM) nucleus which is considered as a major output of the amygdala. These excitatory effects are postsynaptic, mediated by Hcrt2/OX2 receptors and result from the closure of a potassium conductance. They occur on a class of neurons that are also excited by vasopressin acting through V1a receptors. These results suggest that the hcrt/orx system can act through the amygdala to augment arousal and evoke the autonomic and behavioral responses associated with fear, stress or emotion.