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

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.

The chemistry of endocannabinoids.

Over the last two decades a new biochemical/physiological system, now known as the endocannabinoid system, was discovered. Two receptors, cannabinoid receptor type 1 (CB1 receptor) and cannabinoid receptor type 2 (CB2 receptor), have been well characterized and numerous additional ones are in various stages of characterization. Two major endogenous ligands, anandamide and 2-arachidonoyl glycerol (2-AG), have been identified and an enormous amount of research has been reported on them. A few additional endocannabinoids have been identified, but at present our understanding of their physiological roles is limited. The biosynthesis and degradation of the endocannabinoids have been explored, but considerable gaps exist in our knowledge of these processes. In view of the plethora of physiological roles of the endocannabinoid system, numerous academic and industrial labs are making a considerable effort to develop novel drugs, both agonists and antagonists to the endocannabinoid receptors. In the present review, we shall try to give an overview of the chemistry of the endocannabinoids as well as of some synthetic molecules that affect the endocannabinoid system.