AMPA receptor stimulation within the central nucleus of the amygdala elicits a differential activation of central dopaminergic systems.
Appetitive and aversive arousing stimuli increase rates of dopamine (DA) release, particularly within the prefrontal cortex (PFC). Evidence suggests an activating influence of both the central (CeA) and basolateral (BlA) nuclei of the amygdala on DA neurotransmission. For example, lesions of CeA block stressor-induced increases in DA release. Additionally, electrical stimulation of BlA increases DA release in select terminal fields. Previous studies indicate that glutamatergic AMPA receptors modulate CeA and BlA output. However, the extent to which AMPA receptors participate in amygdala-dependent activation of DA neurotransmission is unknown. The current studies examined the effects of bilateral AMPA infusions within CeA or BlA on post-mortem and in vivo microdialysis indices of DA release. Additionally, stress is associated with moderate increases in serotonin (5-HT) neurotransmission that are also blocked by CeA lesions. Thus, the current studies also examined the impact of AMPA infusions on post-mortem indices of 5-HT utilization. AMPA infusion into CeA, but not BlA, increased post-mortem indices of DA and 5-HT release in a pattern comparable to that observed under appetitive/aversive conditions. In vivo microdialysis studies confirmed that AMPA infusions into CeA, but not BlA, increase extracellular PFC DA levels. When infused into sleeping animals, CeA-AMPA infusion also elicited a rapid-onset transition into waking. Thus, CeA-AMPA receptors exert an excitatory influence on DA and 5-HT neurotransmission and on behavioral state. Combined, these results suggest that CeA-AMPA receptors may participate in the coordination of neural systems involved in the regulation of behavioral state under high-arousal conditions.
Stalnaker
Thomas A
TA
Psychology Department, University of Wisconsin-Madison, Madison, WI 53706-1611, USA.
Berridge
Craig W
CW
D000679:Amygdala / Q000187:drug effects* / Q000378:metabolism*; D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000819:agonists* / Q000378:metabolism; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
D018091:Receptors, AMPA; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D004298:Dopamine