We investigated the pharmacology of three novel compounds, Org 27569 (5-chloro-3-ethyl-1H-indole-2-carboxylic acid [2-(4-piperidin-1-yl-phenyl)-ethyl]-amide), Org 27759 (3-ethyl-5-fluoro-1H-indole-2-carboxylic acid [2-94-dimethylamino-phenyl)-ethyl]-amide), and Org 29647 (5-chloro-3-ethyl-1H-indole-2-carboxylic acid (1-benzyl-pyrrolidin-3-yl)-amide, 2-enedioic acid salt), at the cannabinoid CB 1 receptor. In equilibrium binding assays, the Org compounds significantly increased the binding of the CB 1 receptor agonist, indicative of a positively cooperative allosteric effect. The same compounds caused a significant, but incomplete, decrease in the specific binding of the CB 1 receptor inverse agonist studies also validated the allosteric nature of the Org compounds, because they all significantly decreased radioligand dissociation. These data suggest that the Org compounds bind allosterically to the CB 1 receptor and elicit a conformational change that increases agonist affinity for the orthosteric binding site. In contrast to the binding assays, however, the Org compounds behaved as insurmountable antagonists of receptor function; in the reporter gene assay, the guanosine 5Ј-O-(3-[35 S]thio)triphosphate binding assay and the mouse vas deferens assay they elicited a significant reduction in the E max value for CB 1 receptor agonists. The data presented clearly demonstrate, for the first time, that the cannabinoid CB 1 receptor contains an allosteric binding site that can be recognized by synthetic small molecule ligands.Mammalian tissues express at least two types of cannabinoid receptor, CB 1 and CB 2 , both G protein-coupled (for review, see Howlett et al., 2002). CB 1 receptors are found predominantly at central and peripheral nerve terminals where they mediate inhibition of transmitter release. Endogenous ligands for these receptors also exist. These "endocannabinoids" are all eicosanoids, prominent examples including arachidonoylethanolamide (anandamide) and 2-arachidonoyl glycerol, both of which are synthesized on demand, removed from their sites of action by tissue uptake processes and metabolized by intracellular enzymes (Pertwee and Ross,

Background and purpose: A nonpsychoactive constituent of the cannabis plant, cannabidiol has been demonstrated to have low affinity for both cannabinoid CB 1 and CB 2 receptors. We have shown previously that cannabidiol can enhance electrically evoked contractions of the mouse vas deferens, suggestive of inverse agonism. We have also shown that cannabidiol can antagonize cannabinoid receptor agonists in this tissue with a greater potency than we would expect from its poor affinity for cannabinoid receptors. This study aimed to investigate whether these properties of cannabidiol extend to CB 1 receptors expressed in mouse brain and to human CB 2 receptors that have been transfected into CHO cells. Experimental approach: The [ 35 S]GTPgS binding assay was used to determine both the efficacy of cannabidiol and the ability of cannabidiol to antagonize cannabinoid receptor agonists (CP55940 and R-( þ )-WIN55212) at the mouse CB 1 and the human CB 2 receptor. Key results: This paper reports firstly that cannabidiol displays inverse agonism at the human CB 2 receptor. Secondly, we demonstrate that cannabidiol is a high potency antagonist of cannabinoid receptor agonists in mouse brain and in membranes from CHO cells transfected with human CB 2 receptors. Conclusions and implications:This study has provided the first evidence that cannabidiol can display CB 2 receptor inverse agonism, an action that appears to be responsible for its antagonism of CP55940 at the human CB 2 receptor. The ability of cannabidiol to behave as a CB 2 receptor inverse agonist may contribute to its documented anti-inflammatory properties.

4 THCV also antagonized R-( þ )-WIN55212, anandamide, methanandamide and CP55940 in the vas deferens, but with lower apparent K B -values (1.5, 1.2, 4.6 and 10.3 nM, respectively). 5 THCV (100 nM) did not oppose clonidine, capsaicin or (À)-7-hydroxy-cannabidiol-dimethylheptyl-induced inhibition of electrically evoked contractions of the vas deferens. 6 Contractile responses of the vas deferens to phenylephrine hydrochloride or b,g-methylene-ATP were not reduced by 1 mM THCV or R-( þ )-WIN55212, suggesting that THCV interacts with R-( þ )-WIN55212 at prejunctional sites. 7 At 32 mM, THCV did reduce contractile responses to phenylephrine hydrochloride and b,gmethylene-ATP, and above 3 mM it inhibited electrically evoked contractions of the vas deferens in an SR141716A-independent manner. 8 In conclusion, THCV behaves as a competitive CB 1 and CB 2 receptor antagonist. In the vas deferens, it antagonized several cannabinoids more potently than THC and was also more potent against CP55940 and R-( þ )-WIN55212 in this tissue than in brain membranes. The bases of these agonist-and tissue-dependent effects remain to be established.

Cost-effective strategies to maintain healthy active lifestyle in aging populations are required to address the global burden of age-related diseases. ASPREE will examine whether the potential primary prevention benefits of low dose aspirin outweigh the risks in older healthy individuals. Our primary hypothesis is that daily oral 100 mg enteric-coated aspirin will extend a composite primary endpoint termed ‘disability-free life’ including onset of dementia, total mortality, or persistent disability in at least one of the Katz Activities of Daily Living in 19,000 healthy participants aged 65 years and above (‘US minorities’) and 70 years and above (non ‘US minorities’). ASPREE is a double-blind, randomized, placebo-controlled trial of oral 100 mg enteric-coated acetyl salicylic acid (ASA) or matching placebo being conducted in Australian and US community settings on individuals free of dementia, disability and cardiovascular disease (CVD) events. Secondary endpoints are all-cause and cause specific mortality, fatal and non-fatal cardiovascular events, fatal and non-fatal cancer (excluding non-melanoma skin cancer), dementia, mild cognitive impairment, depression, physical disability, and clinically significant bleeding. To 20 September 2013 14383 participants have been recruited. Recruitment and study completion is anticipated in July 2014 and December 2018 respectively. In contrast to other aspirin trials that have largely focused on cardiovascular endpoints, ASPREE has a unique composite primary endpoint to better capture the overall risk and benefit of aspirin to extend healthy independent lifespan in older adults in the US and Australia.