Phasic activation of locus ceruleus neurons by the central nucleus of the amygdala.
The role of the central nucleus of the amygdala (CeN) in modulating output of noradrenaline in the forebrain was evaluated by recording extracellular, single-unit activity from the noradrenergic nucleus locus ceruleus (LC) during stimulation of the CeN. Short high-frequency trains (200 Hz) delivered at 800 microA in the CeN evoked phasic responses in 90% of the neurons recorded in LC. Single pulses were also effective but less reliably. The responses were complex, multiphasic with an initial latency of 10-20 msec. This early peak was diminished or, in some cases, completely blocked by local or intracerebroventricular application of the corticotrophin releasing factor antagonist alpha helical CRF (9-41). The later excitatory peak and subsequent inhibition were not effected by the drug treatment. The results underline the reciprocal functional relationship between the amygdaloid complex and the LC and suggest that the LC might be an important "effector" of CeN activation during learning.
Bouret
Sebastien
S
Neuromodulation and Memory Processes, Unité Mixte de Recherche 7102, Centre National de la Recherche Scientifique, Université Pierre & Marie Curie, 75005 Paris, France.
Duvel
Adam
A
Onat
Selim
S
Sara
Susan J
SJ
D000200:Action Potentials / Q000502:physiology; D000679:Amygdala / Q000502:physiology*; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage; D004333:Drug Administration Routes; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D005071:Evoked Potentials / Q000502:physiology; D006727:Hormone Antagonists / Q000008:administration & dosage; D007276:Injections, Intraventricular; D008125:Locus Coeruleus / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010446:Peptide Fragments / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D018019:Receptors, Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors
D006727:Hormone Antagonists; D010446:Peptide Fragments; D018019:Receptors, Corticotropin-Releasing Hormone; D003346:Corticotropin-Releasing Hormone; C045089:corticotropin releasing hormone (9-41)