Fatty acid binding protein deletion prevents stress‐induced preference for cocaine and dampens stress‐induced corticosterone levels

• Published in: Synapse (New York, N.Y.) N.Y.), 2018-06, Vol.72 (6), p.e22031-n/a
• Main Authors: Hamilton, John, Marion, Matthew, Figueiredo, Antonio, Clavin, Brendan H., Deutsch, Dale, Kaczocha, Martin, Haj‐Dahmane, Samir, Thanos, Panayotis K.
• Format: Article
• Language: English
• Subjects: addiction; Analysis of Variance; Anandamide; Animals; Cannabinoids; Cocaine; conditioned place preference; Conditioning, Operant - drug effects; Corticosterone; Corticosterone - blood; Drug abuse; Drug-Seeking Behavior - drug effects; Drug-Seeking Behavior - physiology; endocannabinoid; Extinction, Psychological - physiology; Fatty acid-binding protein; Fatty Acid-Binding Protein 7 - deficiency; Fatty Acid-Binding Protein 7 - genetics; Fatty Acid-Binding Proteins - deficiency; Fatty Acid-Binding Proteins - genetics; Fatty acids; Fatty-acid amide hydrolase; Female; Hydrolase; Lipid metabolism; Locomotion - genetics; Locomotor activity; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neoplasm Proteins - deficiency; Neoplasm Proteins - genetics; Place preference conditioning; Reinforcement; Reward; Rodents; Stress, Psychological - blood; Stress, Psychological - genetics
• ISSN: 0887-4476; 1098-2396
• DOI: 10.1002/syn.22031

Genetic and pharmacological manipulation of endocannabinoid (eCB) signaling has previously been shown to have an important role on the rewarding properties of drugs of abuse, including cocaine. Recently, fatty acid binding proteins (FABPs) have been proposed as intracellular transporters of the endocannabinoid anandamide (AEA) as well as other bioactive lipids to their catabolic enzyme, fatty acid amide hydrolase (FAAH). The role of these transporters in modulating the brains reward system has yet to be investigated. This study examined the effects of genetic deletion of FABP 5/7 on cocaine preference, as assessed by the Conditioned Place Preference (CPP) paradigm. Male and female wild type (WT) and FABP 5/7 KO mice showed similar acquisition of cocaine CPP, with no differences found in overall locomotor activity. In addition, while male and female WT mice showed stress‐induced CPP for cocaine, male and female FABP 5/7 KO mice failed to show a stress‐induced preference for the cocaine‐paired chamber. Additionally, serum corticosterone levels were analyzed to explore any potential differences in stress response that may be responsible for the lack of stress‐induced preference for cocaine. Serum samples were obtained in animals under basal conditions as well as following a 30‐min tube restraint stress. Male and female FABP 5/7 KO mice showed reduced corticosterone levels under stress compared to their WT counterparts. The reduction in corticosterone response under stress may mediate that lack of a stress‐induced preference for cocaine in the FABP 5/7 KO mice. Thus, the role of FABPs may play an important role in drug‐seeking behavior under stressful conditions. FABP did not have effects on acquisition of cocaine conditioned place preference. FABP 5/7 KO mice (unlike wild type mice) did not show stress‐induced reinstatement of cocaine place preference. This result may be attributed to a reduced stress corticosterone response in the FABP 5/7 KO mice.