Neuropeptide signalling in the central nucleus of the amygdala.

The central amygdala has a rich repertoire of neuropeptides and neuropeptide receptors. The diverse ways in which they modulate neuronal activity and influence synaptic activity are discussed here mostly in the context of fear and anxiety-related behaviour but also with respect to nociception, hunger and satiety and chronic alcohol exposure that often come together with anxiety. It appears that neuropeptides exert rather specific effects on behaviour and physiology that can be quite different from the effects evoked by opto- or chemogenetical stimulation of the central amygdala neurons that synthesise them or express their receptors. Also, neuropeptides might work synergistically or antagonistically to fine-tune the final outcome of sensory processing in the central amygdala and bring about appropriate physiological and behavioural responses to threat. Taken together, we propose that neuropeptide signalling in the central amygdala mainly serves to establish or maintain emotional homeostasis in response to threatening and other sensory stimuli.