The amygdala, panic disorder, and cardiovascular responses

Area of Science:

• Neuroscience
• Psychiatry
• Behavioral Biology

Background:

• The amygdala, particularly the basolateral nucleus (BLA), is crucial for emotional regulation, including fear and anxiety.
• The BLA is under tonic GABAergic inhibition, influencing behavioral and autonomic responses.
• Dysregulation of the BLA is linked to anxiety disorders.

Purpose of the Study:

• To investigate the role of the basolateral amygdala (BLA) in anxiety and autonomic regulation.
• To explore the mechanisms underlying chronic anxiety and panic-like states originating from the BLA.
• To determine the involvement of GABAergic inhibition, neuropeptides, and synaptic plasticity in BLA-mediated anxiety.

Main Methods:

• Acute and repeated pharmacological manipulations of GABAergic inhibition and corticotropin-releasing factor (CRF) in the BLA.
• Assessment of anxiety-like behaviors, conditioned avoidance, and cardiovascular responses.
• Investigation of NMDA-dependent synaptic plasticity, including cyclic AMP and CAM KII pathways.
• Induction of panic-like responses using lactate infusions.

Main Results:

• Acute GABAergic blockade in the BLA increased anxiety-like behavior, avoidance, and cardiovascular activation.
• BLA activation with CRF induced anxiety-like behavior but not cardiovascular changes.
• Repeated BLA activation (priming) led to a chronic anxiety state susceptible to panic attacks.
• Chronic anxiety was associated with reduced basal inhibitory drive in the BLA due to NMDA-dependent plasticity.
• Lactate-induced panic responses involved angiotensin-II mediated BLA activation.

Conclusions:

• The BLA plays a significant role in regulating anxiety and autonomic functions.
• Alterations in BLA inhibitory tone and synaptic plasticity contribute to the development of chronic anxiety and panic disorders.
• Specific neurochemical pathways, including GABAergic, CRF, and angiotensin-II systems, are critical in BLA-mediated anxiety and panic.