Tetrahydrocannabinolic acid is a potent PPARγ agonist with neuroprotective activity

BACKGROUND AND PURPOSE

Phytocannabinoids are produced in Cannabis sativa L. in acidic form and are decarboxylated upon heating, processing and storage. While the biological effects of decarboxylated cannabinoids such as Δ9 -tetrahydrocannabinol have been extensively investigated, the bioactivity of Δ9 -tetahydrocannabinol acid (Δ9 -THCA) is largely unknown, despite its occurrence in different Cannabis preparations. Here we have assessed possible neuroprotective actions of Δ9 -THCA through modulation of PPARγ pathways.

EXPERIMENTAL APPROACH

The effects of six phytocannabinoids on PPARγ binding and transcriptional activity were investigated. The effect of Δ9 -THCA on mitochondrial biogenesis and PPARγ coactivator 1-α expression was investigated in Neuro-2a (N2a) cells. The neuroprotective effect was analysed in STHdhQ111/Q111 cells expressing a mutated form of the huntingtin protein and in N2a cells infected with an adenovirus carrying human huntingtin containing 94 polyQ repeats (mHtt-q94). The in vivo neuroprotective activity of Δ9 -THCA was investigated in mice intoxicated with the mitochondrial toxin 3-nitropropionic acid (3-NPA).

KEY RESULTS

Cannabinoid acids bind and activate PPARγ with higher potency than their decarboxylated products. Δ9 -THCA increased mitochondrial mass in neuroblastoma N2a cells and prevented cytotoxicity induced by serum deprivation in STHdhQ111/Q111 cells and by mutHtt-q94 in N2a cells. Δ9 -THCA, through a PPARγ-dependent pathway, was neuroprotective in mice treated with 3-NPA, improving motor deficits and preventing striatal degeneration. In addition, Δ9 -THCA attenuated microgliosis, astrogliosis and up-regulation of proinflammatory markers induced by 3-NPA.

CONCLUSIONS AND IMPLICATIONS

Δ9 -THCA shows potent neuroprotective activity, which is worth considering for the treatment of Huntington's disease and possibly other neurodegenerative and neuroinflammatory diseases.

The psychoactive plant cannabinoid, Delta9-tetrahydrocannabinol, is antagonized by Delta8- and Delta9-tetrahydrocannabivarin in mice in vivo

BACKGROUND AND PURPOSE

To follow up in vitro evidence that Delta(9)-tetrahydrocannabivarin extracted from cannabis (eDelta(9)-THCV) is a CB(1) receptor antagonist by establishing whether synthetic Delta(9)-tetrahydrocannabivarin (O-4394) and Delta(8)-tetrahydrocannabivarin (O-4395) behave as CB(1) antagonists in vivo.

EXPERIMENTAL APPROACH

O-4394 and O-4395 were compared with eDelta(9)-THCV as displacers of [(3)H]-CP55940 from specific CB(1) binding sites on mouse brain membranes and as antagonists of CP55940 in [(35)S]GTPgammaS binding assays performed with mouse brain membranes and of R-(+)-WIN55212 in mouse isolated vasa deferentia. Their ability to antagonize in vivo effects of 3 or 10 mg kg(-1) (i.v.) Delta(9)-tetrahydrocannabinol in mice was then investigated.

KEY RESULTS

O-4394 and O-4395 exhibited similar potencies to eDelta(9)-THCV as displacers of [(3)H]-CP55940 (K (i)=46.6 and 64.4 nM, respectively) and as antagonists of CP55940 in the [(35)S]GTPgammaS binding assay (apparent K (B)=82.1 and 125.9 nM, respectively) and R-(+)-WIN55212 in the vas deferens (apparent K (B)=4.8 and 3.9 nM respectively). At i.v. doses of 0.1, 0.3, 1.0 and/or 3 mg kg(-1) O-4394 and O-4395 attenuated Delta(9)-tetrahydrocannabinol-induced anti-nociception (tail-flick test) and hypothermia (rectal temperature). O-4395 but not O-4394 also antagonized Delta(9)-tetrahydrocannabinol-induced ring immobility. By themselves, O-4395 and O-4394 induced ring immobility at 3 or 10 mg kg(-1) (i.v.) and antinociception at doses above 10 mg kg(-1) (i.v.). O-4395 also induced hypothermia at 3 mg kg(-1) (i.v.) and above.

CONCLUSIONS AND IMPLICATIONS

O-4394 and O-4395 exhibit similar in vitro potencies to eDelta(9)-THCV as CB(1) receptor ligands and as antagonists of cannabinoid receptor agonists and can antagonize Delta(9)-tetrahydrocannabinol in vivo.

Identification of candidate genes affecting Delta9-tetrahydrocannabinol biosynthesis in Cannabis sativa

RNA isolated from the glands of a Delta(9)-tetrahydrocannabinolic acid (THCA)-producing strain of Cannabis sativa was used to generate a cDNA library containing over 100 000 expressed sequence tags (ESTs). Sequencing of over 2000 clones from the library resulted in the identification of over 1000 unigenes. Candidate genes for almost every step in the biochemical pathways leading from primary metabolites to THCA were identified. Quantitative PCR analysis suggested that many of the pathway genes are preferentially expressed in the glands. Hexanoyl-CoA, one of the metabolites required for THCA synthesis, could be made via either de novo fatty acids synthesis or via the breakdown of existing lipids. qPCR analysis supported the de novo pathway. Many of the ESTs encode transcription factors and two putative MYB genes were identified that were preferentially expressed in glands. Given the similarity of the Cannabis MYB genes to those in other species with known functions, these Cannabis MYBs may play roles in regulating gland development and THCA synthesis. Three candidates for the polyketide synthase (PKS) gene responsible for the first committed step in the pathway to THCA were characterized in more detail. One of these was identical to a previously reported chalcone synthase (CHS) and was found to have CHS activity. All three could use malonyl-CoA and hexanoyl-CoA as substrates, including the CHS, but reaction conditions were not identified that allowed for the production of olivetolic acid (the proposed product of the PKS activity needed for THCA synthesis). One of the PKS candidates was highly and specifically expressed in glands (relative to whole leaves) and, on the basis of these expression data, it is proposed to be the most likely PKS responsible for olivetolic acid synthesis in Cannabis glands.

Cannabidiol, a non-psychoactive component of cannabis and its synthetic dimethylheptyl homolog suppress nausea in an experimental model with rats

Rats display conditioned rejection reactions during an oral infusion of a flavor previously paired with an emetic drug; considerable evidence indicates that these rejection reactions reflect nausea. Here we report that cannabidiol, a major non-psychoactive cannabinoid found in marijuana and its synthetic dimethylheptyl homolog interfere with nausea elicited by lithium chloride and with conditioned nausea elicited by a flavor paired with lithium chloride. These results suggest that cannabinoids without psychoactive side-effects may have therapeutic value in the treatment of chemotherapy-induced nausea.

Relative efficacies of cannabinoid CB1 receptor agonists in the mouse brain

We measured (-)-5-(1,1-dimethylheptyl)-2-[5-hydroxy-2-(3-hydroxypropyl)cyclohe xyl]-phenol (CP 55,940)-, (-)11-OH-delta8-tetrahydrocannabinol-dimethylheptyl (HU-210)-, anandamide- and delta9-tetrahydrocannabinol-stimulated G protein activation in mouse brain using the [35S]GTPgammaS functional assay. The Ki values for these drugs were determined by agonist competition binding with the cannabinoid CB1 receptor antagonist [3H]N-(piperidin-1-yl-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4- methyl-1H-pyrazole-3-carboxamidehydrochloride ([3H]SR141716A). This information was used to calculate the efficacy for drug stimulation of G protein activity. The rank order of efficacy was CP 55,940 > HU-210 > anandamide > delta9-tetrahydrocannabinol with the latter two drugs being partial agonists. Since efficacy values relate receptor occupancy to functional responses, we believe efficacy values are a better measure of drug-mediated functional responses compared with measurements of drug potency.

Cannabimimetic plants: are they new cannabinoidergic modulators?

Phytochemicals and secondary metabolites able to interact with the endocannabinoid system (Cannabimimetics) have been recently described in a broad range of plants and fruits. These findings can open new alternative avenues to explore for the development of novel therapeutic compounds. The cannabinoids regulate many physiological and pathological functions in both animals and plants. Cannabis sativa is the main plant that produces phytocannabinoids inside resins capable to defend the plant from the aggression of parasites and herbivores. Animals produce anandamide and 2-arachidonoyl glycerol, which thanks to binding with main receptors such as type-1 cannabinoid receptor (CB1R) and the type-2 cannabinoid receptor (CB2R) are involved in inflammation processes and several brain functions. Endogenous cannabinoids, enzymes for synthesis and degradation of cannabinoids, and CB1R and CB2R constitute the endocannabinoid system (ECS). Other plants can produce cannabinoid-like molecules such as perrottetinene extracted from Radula perrottetii, or anandamide and 2-arachidonoyl glycerol extracted from some bryophytes. Moreover, several other secondary metabolites can also interact with the ECS of animals and take the name of cannabimimetics. These phytoextracts not derived from Cannabis sativa can act as receptor agonists or antagonist, or enzyme inhibitors of ECS and can be involved in the inflammation, oxidative stress, cancer, and neuroprotection. Finally, given the evolutionary heterogeneity of the cannabimimetic plants, some authors speculated on the fascinating thesis of the evolutionary convergence between plants and animals regarding biological functions of ECS. The review aims to provide a critical and complete assessment of the botanical, chemical and therapeutic aspects of cannabimimetic plants to evaluate their spread in the world and medicinal potentiality.

The anti-inflammatory activities of cannabinoid receptor ligands in mouse peritonitis models

In this report, we describe experiments in which cannabinoid receptor ligands were evaluated for effects on the development of a peritoneal inflammation when elicited in mice with thioglycollate broth or staphylococcus enterotoxin A. The cannabinoid receptor agonists [(-)-11-hydoxy-Delta(8) tetrahydrocannabinol-dimethylheptyl] (HU-210) and [(R)-(+)-[2,3-dihydro-5-methyl-3-[(4-morpholinyl)methyl[pyrrolo[1,2,3-de]1,4-benzoxazin-6-yl](1-naphthalenyl) methanone] (WIN 55212-2) blocked the migration of neutrophils into the peritoneal cavity in response to these inflammatory stimuli. This effect was caused by a delay in the production of the neutrophil chemoattractants, KC and macrophage inflammatory protein-2. HU-210 and WIN 55212-2 blocked neutrophil chemokines and neutrophil migration whether administered subcutaneously (s.c.) or intracerebroventricularly (i.c.v.). Their modulatory effects on the inflammation were antagonized by centrally administered [N-(piperdin-1-yl)-5-(4-chloropheny)-1-(2,4-dichloropheny)-4-methyl-1H-pyrazole-3-carboxamide hydrochloride] (SR141716A), a selective cannabinoid CB(1) receptor antagonist. This latter observation, and the ability of the cannabinoid receptor agonists to suppress the peritoneal inflammation at relatively low doses when administered i.c.v., indicated a role for central cannabinoid CB(1) receptors in the anti-inflammatory activities of HU-210 and WIN 55212-2. The cannabinoid receptor agonists had no effect on monocyte migration elicited by thioglycollate, despite their ability to suppress monocyte chemotactic protein-1 levels in lavage fluids. The cannabinoid CB(2) receptor antagonist, [N-[(1S)-endo-1,3,3-trimethylbicyclo[2.2.1]heptan-2-yl]5-(4-choro-3 methylphenyl)-1-(4-methylbenzyl)pyrazole-3-carboxamide] (SR144528) inhibited the peritoneal inflammation in a manner analogous to that of HU-210 and WIN 55212-2 when administered i.c.v., but it did not appear to act through central cannabinoid CB(1) receptors. The present results add to the body of literature indicating that cannabinoid receptor ligands have diverse anti-inflammatory properties.

Delta(9)-THC, 11-OH-Delta(9)-THC and Delta(9)-THCCOOH plasma or serum to whole blood concentrations distribution ratios in blood samples taken from living and dead people

The recreational use and abuse of Cannabis is continuously increasing in Switzerland. Cannabinoids are very often detected alone or in combination with other drugs in biological samples taken from drivers suspected of driving under the influence of drugs. Moreover, they are also frequently found in blood specimens from people involved in various medico-legal events, e.g. muggings, murders, rapes and working accidents as well. In order to assess the influence of Cannabis exposure on man behavior and performances, it is often needed to estimate the time of Cannabis use. For that purpose two mathematical models have been set up by Huestis and coworkers. These models are based on cannabinoids concentrations in plasma. Because plasma samples are rarely available for forensic determinations in our laboratory, it could be useful to assess the time-laps since Cannabis use through these models from whole blood values. One prerequisite to the use of these models from whole blood values is the knowledge of the plasma to whole blood concentrations distribution ratios of cannabinoids. In this respect, the Delta(9)-THC, 11-OH-Delta(9)-THC and Delta(9)-THCCOOH concentrations were measured in plasma and whole blood taken from eight volunteers who smoke Cannabis on a regular basis. Cannabinoids levels were also determined in "serum" and whole blood samples taken from six corpses. The values of the plasma to whole blood distribution ratios were found to be very similar and their individual coefficient of variation relatively low suggesting that plasma levels could be calculated from whole blood concentrations taken into account a multiplying factor of 1.6. The data obtained postmortem suggest that the distribution of cannabinoids between whole blood and "serum" is scattered over a larger range of values than those determined from living people and that more cannabinoids (mean value of the serum/whole blood concentrations ratios=2.4) can be recovered from the "serum" fraction. The successful use of the mathematical models of Huestis and coworkers may, therefore, rely in part upon the selection of the appropriate blood sample, i.e. plasma. When plasma is not available, whole blood values could be considered with some caution taken into account a multiplying factor of 1.6 to calculate plasma concentrations from blood values. In the case of blood samples taken after death, the use of these models to assess the time of Cannabis use is not recommended.

Cannabinoids

Since the discovery of an endogenous cannabinoid system, research into the pharmacology and therapeutic potential of cannabinoids has steadily increased. Two subtypes of G-protein coupled cannabinoid receptors, CB(1) and CB(1), have been cloned and several putative endogenous ligands (endocannabinoids) have been detected during the past 15 years. The main endocannabinoids are arachidonoyl ethanolamide (anandamide) and 2-arachidonoyl glycerol (2-AG), derivatives of arachidonic acid, that are produced "on demand" by cleavage of membrane lipid precursors. Besides phytocannabinoids of the cannabis plant, modulators of the cannabinoid system comprise synthetic agonists and antagonists at the CB receptors and inhibitors of endocannabinoid degradation. Cannabinoid receptors are distributed in the central nervous system and many peripheral tissues, including immune system, reproductive and gastrointestinal tracts, sympathetic ganglia, endocrine glands, arteries, lung and heart. There is evidence for some non-receptor dependent mechanisms of cannabinoids and for endocannabinoid effects mediated by vanilloid receptors. Properties of CB receptor agonists that are of therapeutic interest include analgesia, muscle relaxation, immunosuppression, anti-inflammation, antiallergic effects, improvement of mood, stimulation of appetite, antiemesis, lowering of intraocular pressure, bronchodilation, neuroprotection and antineoplastic effects. The current main focus of clinical research is their efficacy in chronic pain and neurological disorders. CB receptor antagonists are under investigation for medical use in obesity and nicotine addiction. Additional potential was proposed for the treatment of alcohol and heroine dependency, schizophrenia, conditions with lowered blood pressure, Parkinson's disease and memory impairment in Alzheimer's disease.

Human skin permeation of Delta8-tetrahydrocannabinol, cannabidiol and cannabinol

The purpose of this study was to quantify the in-vitro human skin transdermal flux of Delta8-tetrahydrocannabinol (Delta8-THC), cannabidiol (CBD) and cannabinol (CBN). These cannabinoids are of interest because they are likely candidates for transdermal combination therapy. Differential thermal analysis and in-vitro diffusion studies with human tissue were completed for the compounds. Heats of fusion, melting points and relative thermodynamic activities were determined for the crystalline compounds, CBD and CBN. Flux, permeability, tissue concentration and lag times were measured in the diffusion experiments. CBN had a lower heat of fusion and corresponding higher calculated relative thermodynamic activity than CBD. Ethanol concentrations of 30 to 33% significantly increased the transdermal flux of Delta8-THC and CBD. Tissue concentrations of Delta8-THC were significantly higher than for CBN. Lag times for CBD were significantly smaller than for CBN. The permeabilities of CBD and CBN were 10-fold higher than for Delta8-THC. Combinations of these cannabinoids with ethanol will be further studied in transdermal patch formulations in vitro and in vivo, as significant flux levels of all the drugs were obtained. CBD, the most polar of the three drugs, and other more polar cannabinoids will also be the focus of future drug design studies for improved transdermal delivery rates.

Dimethylheptyl-THC-11 oic acid: a nonpsychoactive antiinflammatory agent with a cannabinoid template structure

OBJECTIVE

To assess the antiinflammatory activity of dimethylheptyl-THC-11 oic acid (DMH-11C), a nonpsychoactive synthetic derivative of tetrahydrocannabinol.

METHODS

Acute inflammation was induced by injection of interleukin-1beta and tumor necrosis factor alpha into subcutaneous air pouches formed on the backs of mice. Inflammation was quantified 6 hours later by pouch fluid leukocyte counts. Adjuvant-induced polyarthritis in rats was used as a model of chronic inflammation and joint tissue injury. Animals were either untreated, treated with safflower oil, or treated with DMH-11C in safflower oil. Arthritis was assessed by clinical observation and by histomorphologic evaluation of tibiotarsal joints.

RESULTS

Oral administration of DMH-11C reduced the accumulation of pouch fluid leukocytes and significantly reduced the severity of adjuvant-induced polyarthritis. Histopathologic studies of tibiotarsal joints showed that DMH-11C treatment attenuated pannus formation and joint tissue injury.

CONCLUSION

DMH-11C suppresses acute inflammation in the subcutaneous air pouch in mice and chronic joint inflammation characteristic of adjuvant disease in rats. These results demonstrate the potential use of this nonpsychoactive cannabinoid as an antiinflammatory agent.

Detection of cannabis in oral fluid (saliva) and forehead wipes (sweat) from impaired drivers

Saliva and sweat have been presented as two alternative matrices for the establishment of drug abuse. The noninvasive collection of a saliva or sweat sample, which is relatively easy to perform and can be achieved under close supervision, is one of the most important benefits in a driving-under-the-influence situation. Moreover, the presence of certain analytes in saliva is a better indication of recent use than when the drug is detected in urine, so there is a higher probability that the subject is experiencing pharmacological effects at the time of sampling. We developed an original procedure using gas chromatography-mass spectrometry to test for delta9-tetrahydrocannabinol (THC), the psychoactive ingredient of cannabis, in oral fluid and forehead wipes, collected with Sarstedt Salivettes and cosmetic pads, respectively. Blood, urine, oral fluid, and forehead wipes were simultaneously collected from 198 injured drivers admitted to an Emergency Hospital in Strasbourg, France. Of the 22 subjects positive for 11-nor-9-carboxy-THC (THCCOOH) in urine, 14 and 16 were positive for THC in oral fluid (1 to 103 ng/Salivette) and forehead wipe (4 to 152 ng/pad), respectively. 11-Hydroxy-THC and THCCOOH were not detected in these body fluids. Two main limitations of saliva and sweat are apparent: the amount of matrix collected is smaller when compared to urine, and the levels of drugs are higher in urine than in saliva and sweat. A current limitation in the use of these specimens for roadside testing is the absence of a suitable immunoassay that detects the parent compound in sufficiently low concentrations.

Synthetic cannabinoid ajulemic acid exerts potent antifibrotic effects in experimental models of systemic sclerosis

BACKGROUND

Cannabinoids modulate fibrogenesis in scleroderma. Ajulemic acid (AjA) is a non-psychoactive synthetic analogue of tetrahydrocannabinol that can bind the peroxisome proliferator-activated receptor-γ (PPAR-γ). Recent evidence suggests a key role for PPAR-γ in fibrogenesis.

OBJECTIVE

To determine whether AjA can modulate fibrogenesis in murine models of scleroderma.

MATERIAL AND METHODS

Bleomycin-induced experimental fibrosis was used to assess the antifibrotic effects of AjA in vivo. In addition, the efficacy of AjA in pre-established fibrosis was analysed in a modified model of bleomycin-induced dermal fibrosis and in mice overexpressing a constitutively active transforming growth factor β (TGFβ) receptor I. Skin fibrosis was evaluated by quantification of skin thickness and hydroxyproline content. As a marker of fibroblast activation, α-smooth muscle actin was examined. To study the direct effect of AjA in collagen neosynthesis, skin fibroblasts from patients with scleroderma were treated with increasing concentrations of AjA. Protein expression of PPAR-γ, and its endogenous ligand 15d-PGJ2, and TGFβ were assessed before and after AjA treatment.

RESULTS

AjA significantly prevented experimental bleomycin-induced dermal fibrosis and modestly reduced its progression when started 3 weeks into the disease. AjA strongly reduced collagen neosynthesis by scleroderma fibroblasts in vitro, an action which was reversed completely by co-treatment with a selective PPAR-γ antagonist.

CONCLUSIONS

AjA prevents progression of fibrosis in vivo and inhibits fibrogenesis in vitro by stimulating PPAR-γ signalling. Since therapeutic doses of AjA are well tolerated in humans, it is suggested that AjA as an interesting molecule targeting fibrosis in patients with scleroderma.

Cannabinoids inhibit excitatory inputs to neurons in the shell of the nucleus accumbens: an in vivo electrophysiological study

The nucleus accumbens (NAc) represents a critical site for the rewarding properties of diverse classes of drugs of abuse. Glutamatergic afferents to the NAc are involved in the actions of psychostimulants and opioids, while the potentiation of dopaminergic neurotransmission in the NAc is a common feature of abused drugs, including cannabinoids. Cannabinoid receptors (CB1) are densely expressed in regions that provide excitatory innervation to the NAc, such as the amygdala, the cortex and the hippocampus. Recent in vitro evidence suggests that indeed cannabinoids modulate glutamatergic synapses in the NAc. In this study we recorded extracellularly from neurons in the shell of the NAc which responded to the stimulation of the baso-lateral amygdala (BLA) or the medial prefrontal cortex (PFC) in urethane anaesthetized rats. BLA or PFC stimulation induced generation of action potentials in NAc neurons. This excitatory effect was strongly inhibited by the synthetic cannabinoid agonists WIN 55212,2 (0.062-0.25 mg/kg, i.v.) and HU-210 (0.125-0.25 mg/kg, i.v.) or the psychoactive principle of Cannabis delta(9)-tetrahydrocannabinol (1.0 mg/kg, i.v.). Neither the D1 or D2 dopamine receptor antagonists (SCH23390 0.5-1.0 mg/kg, sulpiride 5-10 mg/kg, i.v.) or the opioid antagonist naloxone (1.0 mg/kg, i.v.) were able to reverse the action of cannabinoids, while the selective CB1 receptor antagonist/reverse agonist SR141716A (0.5 mg/kg, i.v.) fully suppressed the action of cannabinoid agonists, whereas per se had no significant effect. These results provide evidence that cannabinoids, in common with other drugs of abuse, in vivo strongly inhibit the excitability of neurons in the shell of the NAc.

Neuroprotective and antioxidant activities of HU-211, a novel NMDA receptor antagonist

This study examines the ability of (+)-(3S,4S)-7-hydroxy-delta 6-tetrahydrocannabinol-1,1-dimethylheptyl (HU-211), a non-competitive NMDA receptor antagonist to: (1) rescue neurons in culture from injury evoked by sodium nitroprusside, hydrogen peroxide (H2O2) and oxygen glucose deprivation; and (2) scavenge reactive oxygen species in vitro. Qualitative and quantitative assessments of cell survival have indicated that: (1) Neuronal cell injury produced following deprivation of oxygen and glucose was significantly attenuated by 5 microM HU-211. (2) Glial and neuronal cell damage induced by sodium nitroprusside was markedly ameliorated by 10 microM HU-211. (3) HU-211 reduced protein oxidation initiated by gamma irradiation, and scavenged peroxyl radicals. (4) HU-211 carries an oxidation potential of 550 mV. These findings suggest that HU-211 holds a unique position among putative neuroprotectant agents in that it combines NMDA receptor antagonistic activity and free radical scavenging abilities in a single molecule.

Validated method for the simultaneous determination of Δ9-THC and Δ9-THC-COOH in oral fluid, urine and whole blood using solid-phase extraction and liquid chromatography–mass spectrometry with electrospray ionization

A fully validated, sensitive and specific method for the extraction and quantification of Delta(9)-tetrahydrocannabinol (THC) and 11-nor-9-carboxy-Delta(9)-THC (THC-COOH) and for the detection of 11-hydroxy-Delta(9)-THC (11-OH THC) in oral fluid, urine and whole blood is presented. Solid-phase extraction and liquid chromatography-mass spectrometry (LC-MS) technique were used, with electrospray ionization. Three ions were monitored for THC and THC-COOH and two for 11-OH THC. The compounds were quantified by selected ion recording of m/z 315.31, 329.18 and 343.16 for THC, 11-OH THC and THC-COOH, respectively, and m/z 318.27 and 346.26 for the deuterated internal standards, THC-d(3) and THC-COOH-d(3), respectively. The method proved to be precise for THC and THC-COOH both in terms of intra-day and inter-day analysis, with intra-day coefficients of variation (CV) less than 6.3, 6.6 and 6.5% for THC in saliva, urine and blood, respectively, and 6.8 and 7.7% for THC-COOH in urine and blood, respectively. Day-to-day CVs were less than 3.5, 4.9 and 11.3% for THC in saliva, urine and blood, respectively, and 6.2 and 6.4% for THC-COOH in urine and blood, respectively. Limits of detection (LOD) were 2 ng/mL for THC in oral fluid and 0.5 ng/mL for THC and THC-COOH and 20 ng/mL for 11-OH THC, in urine and blood. Calibration curves showed a linear relationship for THC and THC-COOH in all samples (r(2)>0.999) within the range investigated. The procedure presented here has high specificity, selectivity and sensitivity. It can be regarded as an alternative method to GC-MS for the confirmation of positive immunoassay test results, and can be used as a suitable analytical tool for the quantification of THC and THC-COOH in oral fluid, urine and/or blood samples.

Randomised, double-blind, placebo-controlled trial to assess the potential of cannabinoid receptor stimulation in the treatment of dystonia

Cannabis may have medicinal uses in a variety of diseases. The neural mechanisms underlying dystonia involve abnormalities within the basal ganglia-in particular, overactivity of the lateral globus pallidus (GPl). Cannabinoid receptors are located presynaptically on GABA terminals within the GPi, where their activation reduces GABA reuptake. Cannabinoid receptor stimulation may thus reduce overactivity of the GPl and thereby reduce dystonia. A double-blind, randomised, placebo-controlled, crossover study using the synthetic cannabinoid receptor agonist nabilone in patients with generalised and segmental primary dystonia showed no significant reduction in dystonia following treatment with nabilone.

A reliable and validated LC-MS/MS method for the simultaneous quantification of 4 cannabinoids in 40 consumer products

In the past 50 years, Cannabis sativa (C. sativa) has gone from a substance essentially prohibited worldwide to one that is gaining acceptance both culturally and legally in many countries for medicinal and recreational use. As additional jurisdictions legalize Cannabis products and the variety and complexity of these products surpass the classical dried plant material, appropriate methods for measuring the biologically active constituents is paramount to ensure safety and regulatory compliance. While there are numerous active compounds in C. sativa the primary cannabinoids of regulatory and safety concern are (-)-Δ⁹-tetrahydrocannabinol (THC), cannabidiol (CBD), and their respective acidic forms THCA-A and CBDA. Using the US Food and Drug Administration (FDA) bioanalytical method validation guidelines we developed a sensitive, selective, and accurate method for the simultaneous analysis CBD, CBDA, THC, and THCA-A in oils and THC & CBD in more complex matrices. This HPLC-MS/MS method was simple and reliable using standard sample dilution and homogenization, an isocratic chromatographic separation, and a triple quadrupole mass spectrometer. The lower limit of quantification (LLOQ) for analytes was 0.195 ng/mL over a 0.195-50.0 ng/mL range of quantification with a coefficient of correlation of >0.99. Average intra-day and inter-day accuracies were 94.2-112.7% and 97.2-110.9%, respectively. This method was used to quantify CBD, CBDA, THC, and THCA-A in 40 commercial hemp products representing a variety of matrices including oils, plant materials, and creams/cosmetics. All products tested met the federal regulatory restrictions on THC content in Canada (<10 μg/g) except two, with concentrations of 337 and 10.01 μg/g. With respect to CBD, the majority of analyzed products contained low CBD levels and a CBD: CBDA ratio of <1.0. In contrast, one product contained 8,410 μg/g CBD and a CBD: CBDA ratio of >1,000 (an oil-based product). Overall, the method proved amenable to the analysis of various commercial products including oils, creams, and plant material and may be diagnostically indicative of adulteration with non-hemp C. sativa, specialized hemp cultivars, or unique manufacturing methods.

Altered responsiveness of serotonin receptor subtypes following long-term cannabinoid treatment

This study examined the effects of long-term cannabinoid administration on the responsivity of 5-HT1A and 5-HT2A receptors, which have been implicated in depression. Animals received 12 d administration of the potent cannabinoid receptor agonist HU-210 (100 microg/kg), following which they were monitored on their behavioural, physiological and hormonal responses to a single challenge of a 5-HT1A and 5-HT2A receptor agonist, 8-OH-DPAT (0.3 mg/kg) and DOI (1 mg/kg) respectively. Chronic HU-210 treatment lead to a significant enhancement of DOI-induced wet-dog shakes, but a reduction of DOI-induced back muscle contractions. DOI-induced corticosterone release was unaffected by HU-210 treatment. The hyperthermic response to DOI appeared to be potentiated by long-term HU-210 treatment, as 50% of these subjects died from an apparent serotonin syndrome with core temperatures exceeding 43 degrees C. The 8-OH-DPAT-induced hypothermic response and elevation of corticosterone were both significantly attenuated by long- term HU-210 treatment. These data imply that chronic cannabinoid treatment may up-regulate 5-HT2A receptor activity while concurrently down-regulating 5-HT1A receptor activity, a finding similar to that sometimes observed in depression. This may partially explain the association between excessive cannabis consumption and the induction of affective disease.

Enhancement by chlordiazepoxide of catalepsy induced in rats by intravenous or intrapallidal injections of enantiomeric cannabinoids

The cataleptic response of rats to (-)-delta-9-tetrahydrocannabinol (delta-9-THC), measured using a bar test, was enhanced by subcutaneous pretreatment with chlordiazepoxide (10 mg/kg). Significant potentiation was observed when the cannabinoid was administered peripherally (0.1-1.0 mg/kg i.v.) and when it was injected bilaterally into sites in or very near the posterior medial region of the globus pallidus (30 micrograms). Similar results were obtained with (-)-11-hydroxy-delta-8-dimethylheptyl-THC (0.005 to 0.02 mg/kg i.v. and 3, 10 or 30 micrograms intracerebrally). However, the (+) isomer of the 11-hydroxy compound was inactive in the presence and absence of chlordiazepoxide. It was also found that chlordiazepoxide (10 mg/kg s.c.) enhanced the cataleptic response to the GABA agonist, THIP (0.25 microgram), injected bilaterally into sites located in or very near the globus pallidus and that the cataleptic response to delta-9-THC (1 mg/kg i.v.) could be potentiated by chlordiazepoxide (50 micrograms), when this was injected into similar sites in the brain. The results support the hypothesis that the cataleptic response to cannabinoids is mediated by gamma-aminobutyric acid. They also provide evidence that cannabinoids can produce catalepsy by interacting with tissue in the vicinity of the globus pallidus and that the ability to interact in this way depends on the conformation of the cannabinoid molecule.

Endogenous cannabinoid, 2-arachidonoylglycerol, attenuates naloxone-precipitated withdrawal signs in morphine-dependent mice

In the present study, we examined the effects of endogenous ligand 2-arachidonoylglycerol (2-AG) on naloxone-precipitated withdrawal in morphine-dependent mice, in comparison with that of two cannabinoid agonists, an ingredient of Cannabis sativa Delta(8)-tetrahydrocannabinol (Delta(8)-THC) and the synthetic cannabinoid CB1 receptor agonist HU-210. 2-AG at a dose of 10 microg per mouse (i.c.v.) significantly inhibited both jumping and forepaw tremor as signs of withdrawal following naloxone challenge in morphine-dependent mice. Furthermore, both Delta(8)-THC and HU-210 significantly attenuated these symptoms of withdrawal in morphine-dependent mice. Therefore, it is suggested that inactivation of the endogenous cannabinoid system is related to the induction of withdrawal syndrome in morphine-dependent mice. Moreover, hyperlocomotor activity in morphine-dependent mice was markedly increased by Delta(8)-THC 10 mg/kg, which had no effect in naive mice. This finding suggested that in morphine dependence, upregulation of cannabinoid CB1 receptors occurred. Non-psychoactive CB1 receptor agonists or accelerators of endocannabinoid synthesis may be potential as therapeutic drugs for opiate withdrawal symptoms.

Activation of spinal cannabinoid 1 receptors inhibits C-fibre driven hyperexcitable neuronal responses and increases [35S]GTPgammaS binding in the dorsal horn of the spinal cord of noninflamed and inflamed rats

The analgesic potential of cannabinoid (CB) receptor agonists is of clinical interest. Improved understanding of the mechanisms of action of cannabinoids at sites involved in the modulation of acute and sustained inflammatory nociceptive transmission, such as the spinal cord, is essential. In vivo electrophysiology was used to compare the effect of the synthetic CB agonist, HU210, on acute transcutaneous electrical-evoked responses of dorsal horn neurons of noninflamed anaesthetized rats and anaesthetized rats with a peripheral carrageenin inflammation. CB receptor G-protein coupling in lumbar spinal cord sections of noninflamed and carrageenin-inflamed rats was studied with in vitro autoradiography of guanylyl 5'-[gamma-[35S]thio]triphosphate ([35S]GTPgammaS) binding. Spinal HU210 significantly inhibited the C-fibre-mediated late (300-800 ms) postdischarge response of dorsal horn neurons of noninflamed and carrageenin-inflamed rats; the CB1 receptor antagonist SR141716A blocked the effect of HU210. HU210 had limited effects on A-fibre-evoked dorsal horn neuronal responses of both groups of rats. HU210 significantly increased [35S]GTPgammaS binding in the dorsal horn of the spinal cord of both groups of rats compared with basal [35S]GTPgammaS binding; SR141716A blocked these effects. The predominant effect of spinal HU210, via CB1 receptor activation, was on the C-fibre driven postdischarge responses, a measure of neuronal hyperexcitability following repetitive C-fibre stimulation. Sustained, but not enhanced, antinociceptive effects of HU210 following carrageenin inflammation are reported; CB receptor G-protein coupling was not altered by inflammation. These results strengthen the body of evidence suggesting CB agonists may be an important novel analgesic approach for the treatment of sustained pain states.

Assay of plasma cannabidiol by capillary gas chromatography/ion trap mass spectroscopy following high-dose repeated daily oral administration in humans

Plasma levels of cannabidiol (CBD) were ascertained weekly in 14 Huntington's disease patients undergoing a double-blind, placebo-controlled, crossover trial of oral CBD (10 mg/kg/day = about 700 mg/day) for 6 weeks. The assay procedure involved trimethylsilyl (TMS) derivatization of CBD and the internal standard delta-6-tetrahydrocannabinol (THC), capillary column gas chromatography, ion trap mass spectroscopy in positive ion chemical ionization mode using isobutane, and calculations of CBD levels based on peak ion intensity of the 387 M + H peak of delta-6-THC-TMS and the 459 M + H peak of CBD-2TMS. The sensitivity of the assay was about 500 pg/ml, and the precision was about 10-15%. Mean plasma levels of CBD ranged from 5.9-11.2 ng/ml over the 6 weeks of CBD administration. CBD levels averaged 1.5 ng/ml one week after CBD was discontinued, and were virtually undetectable thereafter. The elimination half-life of CBD was estimated to be about 2-5 days, and there were no differences between genders for half-life or CBD levels. Additionally, no plasma delta-1-THC, the major psychoactive cannabinoid of marijuana, was detected in any subject.

The actions of some cannabinoid receptor ligands in the rat isolated mesenteric artery

1. The actions of a number of cannabinoid receptor ligands were investigated using the myograph-mounted rat isolated mesenteric artery. Anandamide, CP 55,940, HU-210, palmitoylethanolamide and WIN 55,212-2 all caused concentration-dependent relaxations of methoxamine-precontracted vessels which were not affected by removal of the endothelium. 2. Precontracting vessels with 60 mM KCl instead of methoxamine greatly reduced the vasorelaxant effects of anandamide and palmitoylethanolamide. High K+ solution caused a modest decrease in the relaxant potency of CP 55,940 and HU-210, and had no effect on relaxations induced by WIN 55,212-2. 3. Relaxations of methoxamine-induced tone by anandamide, CP 55,940 and HU-210, but not palmitoylethanolamide and WIN 55,212-2, were attenuated by the cannabinoid receptor antagonist, SR 141716A. Relaxation of vessels contracted with 60 mM KCl by CP 55,940 was also sensitive to SR 141716A. 4. Anandamide and CP 55,940 caused small but concentration-dependent contractions in resting vessels in the absence of extracellular calcium. These were not sensitive to SR 141716A. Palmitoylethanolamide and WIN 55,212-2 produced smaller contractions only at higher concentrations. 5. Anandamide and CP 55,940, but not palmitoylethanolamide and WIN 55,212-2, caused concentration-dependent inhibition of the phasic contractions induced by methoxamine in calcium-free conditions, but only anandamide caused inhibition of contractions to caffeine under such conditions. These inhibitory effects were not antagonised by SR 141716A. 6. The present study provides the first detailed investigation of the actions of cannabinoid agonists on vascular smooth muscle. Our results show that these compounds exert both receptor-dependent and -independent effects on agonist-induced calcium mobilization in the rat isolated mesenteric artery.

Antihyperalgesic properties of the cannabinoid CT-3 in chronic neuropathic and inflammatory pain states in the rat

CT-3 (ajulemic acid) is a synthetic analogue of a metabolite of Delta9-tetrahydrocannabinol that has reported analgesic efficacy in neuropathic pain states in man. Here we show that CT-3 binds to human cannabinoid receptors in vitro, with high affinity at hCB1 (Ki 6 nM) and hCB2 (Ki 56 nM) receptors. In a functional GTP-gamma-S assay CT-3 was an agonist at both hCB1 and hCB2 receptors (EC50 11 and 13.4 nM, respectively). In behavioural models of chronic neuropathic and inflammatory pain in the rat, oral administration of CT-3 (0.1-1 mg/kg) produced up to 60% reversal of mechanical hyperalgesia. In both models the antihyperalgesic activity was prevented by the CB1-antagonist SR141716A but not the CB2-antagonist SR144528. In the tetrad of tests for CNS activity, CT-3 (1-10 mg/kg, po) produced dose-related catalepsy, deficits in locomotor performance, hypothermia, and acute analgesia. Comparison of 50% maximal effects in the tetrad and chronic pain assays produced an approximate therapeutic index of 5-10. Pharmacokinetic analysis showed that CT-3 exhibits significant but limited brain penetration, with a brain/plasma ratio of 0.4 measured following oral administration, compared to ratios of 1.0-1.9 measured following subcutaneous administration of WIN55,212-2 or Delta9-THC. These data show that CT-3 is a cannabinoid receptor agonist and is efficacious in animal models of chronic pain by activation of the CB1 receptor. Whilst it shows significant cannabinoid-like CNS activity, it exhibits a superior therapeutic index compared to other cannabinoid compounds, which may reflect a relatively reduced CNS penetration.