title: Morphological and physiological properties of CCK/CB1R-expressing interneurons in the basal amygdala.
abstract: Principal neurons in cortical regions including the basal nucleus of the amygdala (BA) are innervated by several types of inhibitory cells, one of which expresses the neuropeptide cholecystokinin (CCK) and the type 1 cannabinoid receptor (CB1R). CCK/CB1R-expressing interneurons may have a profound impact on amygdalar function by controlling its output. However, very little is known about their properties, and therefore their role in circuit operation cannot be predicted. To characterize the CCK/CB1R-expressing interneurons in the BA, we combined in vitro electrophysiological recordings and neuroanatomical techniques in a transgenic mouse that expresses DsRed fluorescent protein under the control of the CCK promoter. We found that the majority of CCK/CB1R-positive interneurons expressed either the type 3 vesicular glutamate transporter (VGluT3) or the Ca2+binding protein calbindin (Calb). VGluT3+ CCK/CB1R-expressing interneurons targeted the soma of principal neurons more often than Calb+ CCK/CB1R-expressing interneurons, but the dendritic morphology and membrane properties of these two neurochemically distinct interneuron types were not significantly different. The results of paired recordings showed that the unitary IPSC properties of VGluT3+ or Calb+ CCK/CB1R-expressing interneurons recorded in principal neurons were indistinguishable. We verified that endocannabinoids at the output synapses of CCK/CB1R-expressing interneurons could potently reduce the unitary IPSC magnitude. In summary, independent of the neurochemical content, CCK/CB1R-expressing interneurons have similar physiological and morphological properties, providing an endocannabinoid-sensitive synaptic inhibition onto the amygdalar principal neurons.
authors.affiliation: Lendület Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: Laura
authors.initials: L
authors.lastname: Rovira-Esteban
authors.affiliation: Lendület Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Péterfi
authors.affiliation: Lendület Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: Attila
authors.initials: A
authors.lastname: Vikór
authors.affiliation: Division of Medical Gene Technology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Máté
authors.affiliation: Division of Medical Gene Technology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: Gábor
authors.initials: G
authors.lastname: Szabó
authors.affiliation: Lendület Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary. hajos@koki.hu.
authors.forename: Norbert
authors.identifier: http://orcid.org/0000-0002-4582-2708
authors.initials: N
authors.lastname: Hájos
mesh_terms: D026922:Amino Acid Transport Systems, Acidic / Q000378:metabolism; D000679:Amygdala / Q000166:cytology* / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D064026:Calbindins / Q000378:metabolism; D002766:Cholecystokinin / Q000378:metabolism*; D003712:Dendrites; D005260:Female; D007395:Interneurons / Q000166:cytology* / Q000378:metabolism / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials; D008822:Mice, Transgenic; D043884:Receptor, Cannabinoid, CB1 / Q000378:metabolism*; D009435:Synaptic Transmission
chemical_list: D026922:Amino Acid Transport Systems, Acidic; D064026:Calbindins; D002766:Cholecystokinin; D043884:Receptor, Cannabinoid, CB1; C504941:Slc17a8 protein, mouse
keywords: Basal amygdala; CCK; Calbindin; Interneuron; Mouse; VGluT3; Whole-cell patch clamp