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Web End = Brain Struct Funct (2016) 221:33733391 DOI 10.1007/s00429-015-1107-7
http://crossmark.crossref.org/dialog/?doi=10.1007/s00429-015-1107-7&domain=pdf
Web End = ORIGINAL ARTICLE
Structure and function of the amygdaloid NPY system: NPY Y2 receptors regulate excitatory and inhibitory synaptic transmission in the centromedial amygdala
J. Wood1 D. Verma1,5 G. Lach1,2 P. Bonaventure3 H. Herzog4
G. Sperk1 R. O. Tasan1
Received: 24 March 2015 / Accepted: 4 September 2015 / Published online: 13 September 2015 The Author(s) 2015. This article is published with open access at Springerlink.com
Abstract The amygdala is essential for generating emotional-affective behaviors. It consists of several nuclei with highly selective, elaborate functions. In particular, the central extended amygdala, consisting of the central amygdala (CEA) and the bed nucleus of the stria terminalis (BNST) is an essential component actively controlling efferent connections to downstream effectors like hypothalamus and brain stem. Both, CEA and BNST contain high amounts of different neuropeptides that signicantly contribute to synaptic transmission. Among these, neuropeptide Y (NPY) has emerged as an important anxiolytic and fear-reducing neuromodulator. Here, we characterized the expression, connectivity and electro-physiological function of NPY and Y2 receptors within the CEA. We identied several NPY-expressing neuronal populations, including somatostatin- and calretinin-expressing neurons. Furthermore, in the main intercalated nucleus, NPY is expressed primarily in dopamine D1
receptor-expressing neurons but also in interspersed somatostatin-expressing neurons. Interestingly, NPY neurons did not co-localize with the Y2 receptor. Retrograde tract tracing experiments revealed that NPY neurons reciprocally connect the CEA and BNST. Functionally, the Y2 receptor agonist PYY3-36, reduced both, inhibitory as well as excitatory synaptic transmission in the centrome-dial amygdala (CEm). However, we also provide evidence that lack of NPY or Y2 receptors results in increased GABA release specically at inhibitory synapses in the CEm. Taken together, our ndings suggest that NPY expressed by distinct populations of neurons can modulate afferent and efferent projections of the CEA via presynaptic Y2 receptors located at inhibitory and excitatory synapses.
Keywords Neuropeptide Y NPY Y2 receptor Central
amygdala Intercalated neurons Dopamine D1 receptor
Introduction
Neuropeptide Y (NPY) is a 36-amino acid peptide that is widely distributed in the central nervous system. It is particularly known for its involvement in the regulation of appetite, pain perception and maintenance of energy homeostasis, but also for its anxiolytic properties. Recently an involvement in...