Expression and localization of CB1R, NAPE-PLD, and FAAH in the vervet monkey nucleus accumbens

Ryan Kucera,Anders Fink-Jensen,Jean-François Bouchard,Roberta Palmour,Maurice Ptito,Joseph Bouskila,Laurent Elkrief

doi:10.1038/s41598-018-26826-2

Abstract

Extensive rodent literature suggests that the endocannabinoid (eCB) system present in the nucleus accumbens (NAc) modulates dopamine (DA) release in this area. However, expression patterns of the cannabinoid receptor type 1 (CB1R), the synthesizing enzyme N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD), and the degradation enzyme fatty acid amide hydrolase (FAAH) in the NAc have not yet been described in non-human primates. The goal of this study is therefore to characterize the expression and localization of the eCB system within the NAc of vervet monkeys (Chlorocebus sabaeus) using Western blots and immunohistochemistry. Results show that CB1R, NAPE-PLD, and FAAH are expressed across the NAc rostrocaudal axis, both in the core and shell. CB1R, NAPE-PLD, and FAAH are localized in medium spiny neurons (MSNs) and fast-spiking GABAergic interneurons (FSIs). Dopaminergic projections and astrocytes did not express CB1R, NAPE-PLD, or FAAH. These data show that the eCB system is present in the vervet monkey NAc and supports its role in the primate brain reward circuit.

Highlights

The endocannabinoid system is widely expressed in the central nervous system (CNS)
We investigated the expression of three elements of the eCB system by evaluating the total amounts of CB1R and eCB-synthesizing (NAPE-PLD) and degradative (FAAH) enzymes in the monkey nucleus accumbens (NAc)
Immunoblots of three unfixed vervet NAc homogenates incubated with CB1R, N-acyl phosphatidylethanolamine (NAPE)-PLD, and fatty acid amide hydrolase (FAAH) antisera are shown in Fig. 1 and demonstrate their presence in the NAc

Summary

Introduction

The endocannabinoid (eCB) system is widely expressed in the central nervous system (CNS). The expression of CB1R is found in many structures of the mouse, rat, monkey, and human brain, including the amygdala, cingulate cortex, prefrontal cortex (PFC), ventral pallidum, caudate, putamen, nucleus accumbens (NAc), ventral tegmental area (VTA) and lateral hypothalamus[7,8,9,10]. These regions are involved in reward, addiction and cognitive function. There is, no available data for the primate NAc and it is the aim of this study to examine the expression and the precise localization of the eCB system components, namely CB1R, NAPE-PLD, and FAAH, in the vervet monkey NAc

Objectives

Methods

Results

Conclusion