Abstract
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.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Action Potentials / drug effects
-
Action Potentials / physiology
-
Amygdala / drug effects
-
Amygdala / metabolism*
-
Animals
-
Arousal / drug effects
-
Arousal / physiology
-
Excitatory Postsynaptic Potentials / drug effects
-
Excitatory Postsynaptic Potentials / physiology*
-
Fear / drug effects
-
Fear / physiology
-
Intracellular Signaling Peptides and Proteins / metabolism*
-
Intracellular Signaling Peptides and Proteins / pharmacology
-
Neural Pathways / drug effects
-
Neural Pathways / metabolism*
-
Neurons / drug effects
-
Neurons / metabolism*
-
Neuropeptides / metabolism*
-
Neuropeptides / pharmacology
-
Orexin Receptors
-
Orexins
-
Organ Culture Techniques
-
Potassium Channels / drug effects
-
Potassium Channels / metabolism
-
Rats
-
Receptors, G-Protein-Coupled / drug effects
-
Receptors, G-Protein-Coupled / metabolism
-
Receptors, Neuropeptide / drug effects
-
Receptors, Neuropeptide / metabolism
-
Receptors, Vasopressin / agonists
-
Receptors, Vasopressin / metabolism
-
Stress, Psychological / metabolism
-
Stress, Psychological / physiopathology
-
Synaptic Transmission / drug effects
-
Synaptic Transmission / physiology*
-
Vasopressins / metabolism
-
Vasopressins / pharmacology
Substances
-
Intracellular Signaling Peptides and Proteins
-
Neuropeptides
-
Orexin Receptors
-
Orexins
-
Potassium Channels
-
Receptors, G-Protein-Coupled
-
Receptors, Neuropeptide
-
Receptors, Vasopressin
-
Vasopressins