Targeting the endocannabinoid metabolic enzymes to reduce inflammatory pain

i Chapter 1: Introduction . 1 Cannabinoid Discovery and Background . 1 Endocannabinoid System . 1 Cannabinoid Receptors . 2 Biosynthesis and degradation of Endocannabinoids . 5 Overview of Pain:. 9 Inflammation . 12 Preclinical pain models . 13 Analgesics . 16 Cannabis in clinical model of pain: . 18 Role of direct cannabinoid receptor agonists on pain: . 19 Role of DAGL inhibition in antinociceptive effects . 21 Role of FAAH inhibition in antinociceptive effects . 23 Review of studies examining FAAH inhibitors in preclinical pain assays. 27 Role of MAGL inhibition in antinociceptive effects . 29 Rational and Hypothesis: . 32 Carrageenan model of inflammatory pain . 32 Selection of DAGL MAGL and FAAH inhibitors . 34 Chapter 2. The monoacylglycerol lipase inhibitor JZL184 suppresses inflammatory pain in the mouse carrageenan model . 40 Introduction . 40 Methods . 42 Results: . 46 Induction of Edema and allodynia by carrageenan . 46 Anti-edematous and anti-allodynic effects of diclofenac, JZL184, and PF-3845 in the carrageenan model . 47 Cannabinoid receptors mediate the anti-allodynic and anti-edematous of JZL184 . 49 Differential tolerance following repeated administration of low dose and high dose JZL184 . 54 JZL184 reverses carrageenan-induced anti-edema and allodynia . 55 Discussion . 58 Chapter 3. Combined inhibition of MAGL and FAAH suppresses edema and produces augmented anti-allodynic effects in the carrageenan mouse model . 63 Introduction: . 63 Methods: . 66 Results: . 75 Co-administration of JZL184 and PF-3845 elevates endocannabinoids without decreasing arachidonic acid in the brain. 75 Partial MAGL and complete FAAH inhibition produce augmented anti-allodynic effects in the carrageenan model of inflammatory pain . 77 Partial MAGL and complete FAAH inhibition produce augmented anti-allodynic effects in the chronic constriction injury model of neuropathic pain . 79 Combination JZL184 and PF-3845 mediates its anti-allodynic effects through cannabinoid receptors. 80 Repeated administration of the combination of JZL184 and PF-3845 elevate endocannabinoids and decrease arachidonic acid in the brain. 82 Consequences of combined partial MAGL inhibition and full FAAH inhibition given repeatedly. 83 JZL-184 (4mg/kg) with PF-3845 10 (mg/kg) do not elicit cannabimimetic effects, as assessed in the tetrad assay . 84 Partial MAGL and complete FAAH blockade does not cause cross-tolerance to the pharmacological effects of THC. 85 CB1 receptor activity and expression are maintained following repeated administration of JZL184 + PF-3845 combination . 86 CB1 receptor function in the cingulated cortex is maintained following chronic partial MAGL and complete FAAH blockade . 87 Discussion: . 89 Anti-allodynic effects of SA-57, dual FAAH, and MAGL inhibitor with differential potencies, in the carrageenan model of inflammatory pain . 96 Results . 99 Administration of different doses of SA-57 elevates endocannabinoids and decrease arachidonic acid in the brain . 99 Anti-edematous and anti-allodynic effects of SA-57 in the carrageenan model . 100 Cannabinoid receptors mediate the anti-allodynic and anti-edematous of SA-57 . 101 SA-57-induced cannabimimetic effects, as assessed in the tetrad assay . 102 Discussion: . 103 Chapter 4. KT-109, a selective diacylglycerol lipase beta inhibitor reverses LPS-induced allodynia in mice . 107 Introduction . 107 Materials and methods . 110 Results: . 113 Anti-allodynic effects of KT-109 is maintained over an extended period . 113 DAGL- inhibition with KT-109 but not KT-172 reverse LPS-induced allodynia, negative control probe KT-195 does produce any effect . 114 DAGL knockout mice show anti-allodynic phenotype . 116 Repeated administration of KT-109 does not lead to tolerance . 116 Anti-allodynic effects of KT-109 are not mediated by cannabinoid receptors . 117 KT-109 did not produce cannabimimetic effects in tetrad . 118 DAGL- inhibition with high dose KT-109 does not elicit gastric ulcers in mice . 119 Discussion: . 121 Chapter 5. General Discussion . 124 Inhibition of FAAH or MAGL reduces carrageenan-induced inflammatory pain . 127 Simultaneous partial MAGL and complete FAAH inhibition reducing carrageenan-induced inflammatory pain . 130 Inhibit