%0 Journal Article
%T Localization of the cannabinoid CB1 receptor and the 2-AG synthesizing (DAGL¦Á) and degrading (MAGL, FAAH) enzymes in cells expressing the Ca2+-binding proteins calbindin, calretinin and parvalbumin in the adult rat hippocampus
%A Patricia Rivera
%A Sergio Arrabal
%A Manuel Cifuentes
%A Jes¨²s M. Grondona
%A Leticia Rubio
%A Antonio Vargas Fuentes
%A Antonia Serrano
%A Francisco Javier Pavon
%A Juan Suarez
%A Fernando Rodr¨ªguez de Fonseca
%J Frontiers in Neuroanatomy
%D 2014
%I Frontiers Media
%R 10.3389/fnana.2014.00056
%X The retrograde suppression of the synaptic transmission by the endocannabinoid sn-2-arachidonoylglycerol (2-AG) is mediated by the cannabinoid CB1 receptors and requires the elevation of intracellular Ca2+ and the activation of specific 2-AG synthesizing (i.e. DAGL¦Á) enzymes. However, the anatomical organization of the neuronal substrates that express 2-AG/CB1 signaling system-related molecules associated with selective Ca2+-binding proteins (CaBPs) is still unknown. For this purpose, we used double-label immunofluorescence and confocal laser scanning microscopy for the characterization of the expression of the 2-AG/CB1 signaling system (CB1 receptor, DAGL¦Á, MAGL and FAAH) and the CaBPs calbindin D28k, calretinin and parvalbumin in the rat hippocampus. CB1, DAGL¦Á and MAGL labeling was mainly localized in fibers and neuropil, which were differentially organized depending on the hippocampal CaBPs-expressing cells. CB1+ fiber terminals localized in all hippocampal principal cell layers were tightly attached to calbindin+ cells (granular and pyramidal neurons), and calretinin+ and parvalbumin+ interneurons. DAGL¦Á neuropil labeling was selectively found surrounding calbindin+ principal cells in the dentate gyrus and CA1, and in the calretinin+ and parvalbumin+ interneurons in the pyramidal cell layers of the CA1/3 fields. MAGL+ terminals were only observed around CA1 calbindin+ pyramidal cells, CA1/3 calretinin+ interneurons and CA3 parvalbumin+ interneurons localized in the pyramidal cell layers. Interestingly, calbindin+ pyramidal cells expressed FAAH specifically in the CA1 field. The identification of anatomically related-neuronal substrates that expressed 2-AG/CB1 signaling system and selective CaBPs should be considered when analyzing the cannabinoid signaling associated with hippocampal functions.
%K Cannabinoid receptor
%K 2-Arachidonoylglycerol
%K calcium-binding protein
%K Hippocampus
%K rat
%K Immunohistochemistry
%K confocal microscopy
%U http://www.frontiersin.org/Journal/10.3389/fnana.2014.00056/abstract