Dual blockade of FAAH and MAGL identifies behavioral processes regulated by endocannabinoid crosstalk in vivo

Abstract

⌬ 9 -Tetrahydrocannabinol (THC), the psychoactive component of marijuana, and other direct cannabinoid receptor (CB1) agonists produce a number of neurobehavioral effects in mammals that range from the beneficial (analgesia) to the untoward (abuse potential). Why, however, this full spectrum of activities is not observed upon pharmacological inhibition or genetic deletion of either fatty acid amide hydrolase (FAAH) or monoacylglycerol lipase (MAGL), enzymes that regulate the two major endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG), respectively, has remained unclear. Here, we describe a selective and efficacious dual FAAH/MAGL inhibitor, JZL195, and show that this agent exhibits broad activity in the tetrad test for CB1 agonism, causing analgesia, hypomotilty, and catalepsy. Comparison of JZL195 to specific FAAH and MAGL inhibitors identified behavioral processes that were regulated by a single endocannabinoid pathway (e.g., hypomotility by the 2-AG/MAGL pathway) and, interestingly, those where disruption of both FAAH and MAGL produced additive effects that were reversed by a CB1 antagonist. Falling into this latter category was drug discrimination behavior, where dual FAAH/MAGL blockade, but not disruption of either FAAH or MAGL alone, produced THC-like responses that were reversed by a CB1 antagonist. These data indicate that AEA and 2-AG signaling pathways interact to regulate specific behavioral processes in vivo, including those relevant to drug abuse, thus providing a potential mechanistic basis for the distinct pharmacological profiles of direct CB1 agonists and inhibitors of individual endocannabinoid degradative enzymes.hydrolase ͉ inhibitor ͉ metabolism N -arachidonoyl ethanolamine (anandamide or AEA) (1) and 2-arachidonoylglycerol (2-AG) (2, 3) are lipid transmitters that serve as endogenous ligands for the cannabinoid G-proteincoupled receptors CB1 and CB2. These lipids and receptors, along with the enzymes that biosynthesize and degrade AEA and 2-AG, form the endogenous cannabinoid (endocannabinoid) system, which regulates a diverse number of physiological processes in mammals, including pain, cognition, emotionality, neurodegeneration, feeding, and inflammation (4).CB1 and CB2 receptors are also activated by ⌬ 9 -tetrahydrocannabinol (THC), the psychoactive component of marijuana (4). Most of the neurobehavioral effects of THC and other direct cannabinoid receptor agonists are mediated by the CB1 receptor (5, 6), likely reflecting its widespread and abundant expression in the nervous system (7,8). CB1 agonism produces medicinally useful activities, such as analgesia, but also a number of undesirable side effects, including locomotor and cognitive impairments, as well as abuse liability. To date, it has proved difficult to uncouple these beneficial and untoward properties, thus limiting the therapeutic utility of direct CB1 agonists.Inhibitors of AEA and 2-AG degradation offer a potentially attractive alternative strategy to stimulate the endocannabinoid system (9-12). Indeed, d...

Therapeutic Potential of Inhibitors of Endocannabinoid Degradation for the Treatment of Stress-Related Hyperalgesia in an Animal Model of Chronic Pain

“…Indeed, URB597 administration was effective in decreasing the mechanical hyperalgesia and the anxiety-like behavior induced by CUS in mice even in more challenging anxiety tests (EPM), whereas JZL184, consistent with previous reports (Sciolino et al, 2011;Sumislawski et al, 2011), was not. Interestingly, simultaneous inhibition of FAAH and MAGL (combo), known to induce analgesia in mice (Long et al, 2009b), did not elicit further alleviation of the CUSinduced anxiety and hyperalgesia as compared with individual drug administration. Notably, in our experiments, neither URB597, JZL184, nor combo treatment reversed the depression-like behavior observed in CUS mice.…”

“…URB597 treatment had no significant effects in control mice (Figure 2e and f). To investigate whether the anxiety-and depression-like behaviors induced by JZL184 and combo in control mice resulted from drug-induced cannabimimetic effects, as reported for high doses of JZL184 and combined fatty acid amide hydrolase (FAAH)/monoacylglycerol lipase (MAGL) inhibitors (Long et al, 2009b;Wise et al, 2012), we tested mice in the tetrad behavioral paradigm. We found that temperature, catalepsy (bar test), and locomotion (EPM and open field tests) were not changed in drug-treated mice as compared with vehicle-treated animals (data not shown).…”

Equipotent Inhibition of Fatty Acid Amide Hydrolase and Monoacylglycerol Lipase – Dual Targets of the Endocannabinoid System to Protect against Seizure Pathology

“…It is proposed that AM6701 exerts a synergistic action on the endocannabinoid system by acting on AEA and 2-AG responses to protect against seizures. According to Long et al [66], dual augmentation of the AEA and 2-AG signaling pathways allows these 2 lipid transmitters to engage in extensive crosstalk. A critical balance between AEA and 2-AG levels, controlled by endocannabinoid synthesizing and metabolizing enzymes, may therefore be important for normal physiological processes, as well as to promote repair after pathological events [1,45,48,67].…”

The Volitional Nature of Nicotine Exposure Alters Anandamide and Oleoylethanolamide Levels in the Ventral Tegmental Area

“…Brains were sliced (50 mm) at À 10 1C to confirm probe placement into the VTA, and the alternate side was sliced (500 mm) and punched for the VTA (Supplementary Methods). Brain punches were processed and analyzed for fatty acid amide hydrolase (FAAH) activity using previously published methodology (Long et al, 2009). VTA punches were homogenized in icecold PBS, and FAAH activity determined by incubating 100 ml of protein homogenate (0.5 mg/ml, PBS) with 100 mM d 8 -AEA in glass vials (37 1C for 30 min).…”