Excitatory action of hypocretin/orexin on neurons of the central medial amygdala.
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.
Bisetti
A
A
Département des Neurosciences Fondamentales, Centre Médical Universitaire, 1 rue Michel-Servet, 1211 Genève 4, Switzerland.
Cvetkovic
V
V
Serafin
M
M
Bayer
L
L
Machard
D
D
Jones
B E
BE
Mühlethaler
M
M
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000679:Amygdala / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001143:Arousal / Q000187:drug effects / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D005239:Fear / Q000187:drug effects / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism* / Q000494:pharmacology; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism* / Q000494:pharmacology; D064446:Orexin Receptors; D000068797:Orexins; D009924:Organ Culture Techniques; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D043562:Receptors, G-Protein-Coupled / Q000187:drug effects / Q000378:metabolism; D018013:Receptors, Neuropeptide / Q000187:drug effects / Q000378:metabolism; D017483:Receptors, Vasopressin / Q000819:agonists / Q000378:metabolism; D013315:Stress, Psychological / Q000378:metabolism / Q000503:physiopathology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D014667:Vasopressins / Q000378:metabolism / Q000494:pharmacology
D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D064446:Orexin Receptors; D000068797:Orexins; D015221:Potassium Channels; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide; D017483:Receptors, Vasopressin; D014667:Vasopressins