Unraveling the molecular basis of cannabidiolic acid methyl Ester's anti-depressive effects in a rat model of treatment-resistant depression

• Published in: Journal of psychiatric research 2024-07, Vol.175, p.50-59
• Main Authors: Hen-Shoval, D., Indig-Naimer, T., Moshe, L., Kogan, N.M., Zaidan, H., Gaisler-Salomon, I., Okun, E., Mechoulam, R., Shoval, G., Zalsman, G., Weller, A.
• Format: Article
• Language: English
• Subjects: Amidohydrolases - metabolism; Animals; Antidepressive Agents - administration & dosage; Antidepressive Agents - pharmacology; Behavior, Animal - drug effects; Brain-Derived Neurotrophic Factor - drug effects; Brain-Derived Neurotrophic Factor - metabolism; Cannabidiolic acid methyl ester; Cannabinoids - administration & dosage; Cannabinoids - pharmacology; Corticosterone - blood; Depressive Disorder, Treatment-Resistant - drug therapy; Disease Models, Animal; Endocannabinoid system; Genetic animal models of depression; Hippocampus - drug effects; Hippocampus - metabolism; Imipramine - administration & dosage; Imipramine - pharmacology; Major depression disorder; Male; Molecular mechanisms; Prefrontal Cortex - drug effects; Prefrontal Cortex - metabolism; Rats; Rats, Inbred WKY; Receptor, Cannabinoid, CB1 - drug effects; Receptor, Cannabinoid, CB1 - metabolism; Wistar–Kyoto (WKY)
• ISSN: 0022-3956; 1879-1379; 1879-1379
• DOI: 10.1016/j.jpsychires.2024.04.033

Major depressive disorder (MDD) stands as a significant cause of disability globally. Cannabidiolic Acid-Methyl Ester (CBDA-ME) (EPM-301, HU-580), a derivative of Cannabidiol, demonstrates immediate antidepressant-like effects, yet it has undergone only minimal evaluation in psychopharmacology. Our goal was to investigate the behavioral and potential molecular mechanisms associated with the chronic oral administration of this compound in the Wistar Kyoto (WKY) genetic model of treatment-resistant depression. Male WKY rats were subjected to behavioral assessments before and after receiving chronic (14-day) oral doses of CBDA-ME (0.5 mg/kg), 15 mg/kg of imipramine or vehicle. At the end of the study, plasma corticosterone levels and mRNA expression of various genes in the medial Prefrontal Cortex and Hippocampus were measured. Behavioral outcomes from CBDA-ME treatment indicated an antidepressant-like effect similar to imipramine, as oral ingestion reduced immobility and increased swimming duration in the Forced Swim Test. Neither treatment influenced locomotion in the Open Field Test nor preference in the Saccharin Preference Test. The behavioral impact in WKY rats coincided with reduced corticosterone serum levels, upregulated mRNA expression of Cannabinoid receptor 1, Fatty Acid Amide Hydrolase, and Corticotropin-Releasing Hormone Receptor 1, alongside downregulation of the Serotonin Transporter in the hippocampus. Additionally, there was an upregulation of CB1 mRNA expression and downregulation of Brain-Derived Neurotrophic Factor in the mPFC. These findings contribute to our limited understanding of the antidepressant effects of CBDA-ME and shed light on its potential psychopharmacological mechanisms. This discovery opens up possibilities for utilizing cannabinoids in the treatment of major depressive disorder and related conditions. •Cannabinoids have demonstrated potential in the treatment of MDD.•In this study chronic oral ingestion of CBDA- ME was explored in male WKY.•Anti-Depressive-like effect was found in addition to reduced CORT serum levels.•Possible molecular changes were found in the rat's hippocampus and mPFC.•This study exhibits novel discoveriess for utilizing cannabinoids for MDD.