Behavioral effects induced by the cannabidiol analogs HU-502 and HU-556

Cannabidiol is a phytocannabinoid that lacks the psychotomimetic properties of Δ9-tetrahydrocannabinol (THC), the main psychoactive Cannabis sativa component. Cannabidiol has several potential therapeutic properties, including anxiolytic, antidepressant, and antipsychotic; however, cannabidiol has low oral bioavailability, which can limit its clinical use. Here, we investigated if two cannabidiol analogs, HU-502 and HU-556, would be more potent than cannabidiol in behavioral tests predictive of anxiolytic, antidepressant, and antipsychotic effects. Different doses (0.01-3 mg/kg; intraperitoneally) of HU-556 and HU-502 were tested in male Swiss mice submitted to the elevated plus maze (EPM), forced swimming test (FST), and amphetamine-induced-prepulse inhibition (PPI) disruption and hyperlocomotion. Cannabidiol is effective in these tests at a dose range of 15-60 mg/kg in mice. We also investigated if higher doses of HU-556 (3 and 10 mg/kg) and HU-502 (10 mg/kg) produced the cannabinoid tetrad (hypolocomotion, catalepsy, hypothermia, and analgesia), which is induced by THC-like compounds. HU-556 (0.1 and 1 mg/kg) increased the percentage of open arm entries (but not time) in the EPM, decreased immobility time in the FST, and attenuated amphetamine-induced PPI disruption. HU-502 (1 and 3 mg/kg) decreased amphetamine-induced hyperlocomotion and PPI impairment. HU-556, at high doses, caused catalepsy and hypolocomotion, while HU-502 did not. These findings suggest that similar to cannabidiol, HU-556 could induce anxiolytic, antidepressant, and antipsychotic-like effects and that HU-502 has antipsychotic properties. These effects were found at a dose range devoid of cannabinoid tetrad effects.

Novel Synthesis of C-Methylated Phytocannabinoids Bearing Anti-inflammatory Properties

There is growing interest in non-psychoactive phytocannabinoids, namely cannabidiol (CBD), cannabigerol (CBG), and cannabichromene, as potential leads for novel therapeutic agents. In this study, we report on the development of new derivatives in which we methylated either position 4 of olivetol or the phenolic positions of olivetol, or both. We introduce a refinement on previously reported chemical procedures for phytocannabinoid derivatization as well as the biological evaluation of all derivatives in anti-inflammatory in vivo models. Compounds such as the CBD derivative, 2 and the CBG derivative, 11, significantly reduced cytokine levels when compared to their parent compounds. Moreover, both of these derivatives proved to be as potent as dexamethasone for the inhibition of IL-1β. We believe that these new derivatives, as described herein, can be further developed as novel drug candidates for inflammatory conditions.

The Long-Term Effect of a Quality Improvement Intervention in the Management of Bronchiolitis

Quality improvement interventions have been shown to improve adherence with bronchiolitis treatment guidelines; however, the long-term effect of these interventions is unclear. We show that while such an intervention led to a long-lasting change, this was attenuated with time. Repeated interventions are required to maintain guideline adherence.

Long-Term Stability of Lorazepam in Sodium Chloride 0.9% Stored at Different Temperatures in Different Containers

Background and Objective: Infusion containing lorazepam is used by geriatric department to limit anxiety disorders in the elderly. Currently, these infusions are prepared according to demand by the nursing staff, but the preparation in advance in a centralized service could improve quality of preparation and time management. The aim of this study was to investigate the long-term stability of this infusion in polypropylene syringes stored at 5 ± 3°C. Then, results obtained were compared with stability data of lorazepam in syringes stored at room temperature, glass bottles at 5 ± 3°C, and glass bottles at room temperature. Method: Eight syringes and 6 bottles of infusion were prepared by diluting 1 mL lorazepam 4 mg in 23 mL of NaCl 0.9% under aseptic conditions. Five syringes and 3 bottles were stored at 5 ± 3°C and 3 syringes and 3 bottles were stored at room temperature for 30 days. During the storage period, particle appearance or color change were periodically checked by visual and microscope inspection. Turbidity was assessed by measurements of optical density (OD) at 3 wavelengths (350 nm, 410 nm, 550 nm). The stability of pH was also evaluated. The lorazepam concentrations were measured at each time point by high-performance liquid chromatography with ultraviolet detector at 220 nm. Results: Solutions were physically unstable in syringes at 5 ± 3°C after 4 days: crystals and a drop of OD at 350 nm were observed. However, pH was stable. After 2 days, solutions were considered as chemically unstable because a loss of lorazepam concentration higher than 10% was noticed: the lower 1-sided confidence limit at 95% was below 90% of the initial concentration. To assess temperature and polypropylene influence, results were compared with those obtained for syringes at room temperature and bottles at 5 ± 3°C and room temperature. Precipitation, drop of OD at 350 nm, and chemical instability were observed in all conditions. Conclusion: Solutions of lorazepam were unstable after 2 days in syringes at 5 ± 3°C. Preparation in advance appears, therefore, not possible for the clinical use. Storage conditions (temperature and form) do not improve the stability.

Antinociceptive effects of HUF-101, a fluorinated cannabidiol derivative

Cannabidiol (CBD) is a phytocannabinoid with multiple pharmacological effects and several potential therapeutic properties. Its low oral bioavailability, however, can limit its clinical use. Preliminary results indicate that fluorination of the CBD molecule increases its pharmacological potency. Here, we investigated whether HUF-101 (3, 10, and 30mg/kg), a fluorinated CBD analogue, would induce antinociceptive effects. HUF-101 effects were compared to those induced by CBD (10, 30, and 90mg/kg) and the cannabinoid CB_1/2 receptor agonist WIN55,212-2 (1, 3, and 5mg/kg). These drugs were tested in male Swiss mice submitted to the following models predictive to antinociceptive drugs: hot plate, acetic acid-induced writhing, and carrageenan-induced inflammatory hyperalgesia. To evaluate the involvement of CB₁ and CB₂ receptors in HUF-101 and CBD effects, mice received the CB₁ receptor antagonist AM251 (1 or 3mg/kg) or the CB₂ receptor antagonist AM630 (1 or 3mg/kg) 30min before HUF-101, CBD, or WIN55,212-2. In the hot plate test, HUF-101 (30mg/kg) and WIN55,212-2 (5mg/kg) induced antinociceptive effects, which were attenuated by the pretreatment with AM251 and AM630. In the abdominal writhing test, CBD (30 and 90mg/kg), HUF-101 (30mg/kg), and WIN55,212-2 (3 and 5mg/kg) induced antinociceptive effects indicated by a reduction in the number of writhing. Whereas the pretreatment with AM630 did not mitigate the effects induced by any drug in this test, the pretreatment with AM251 attenuated the effect caused by WIN55,212-2. In the carrageenan-induced hyperalgesia test, CBD (30 and 90mg/kg), HUF-101 (3, 10 and 30mg/kg) and WIN55,212-2 (1mg/kg) decreased the intensity of mechanical hyperalgesia measured by the electronic von Frey method. The effects of all compounds were attenuated by the pretreatment with AM251 and AM630. Additionally, we evaluated whether HUF-101 would induce the classic cannabinoid CB₁ receptor-mediated tetrad (hypolocomotion, catalepsy, hypothermia, and antinociception). Unlike WIN55,212-2, CBD and HUF-101 did not induce the cannabinoid tetrad. These findings show that HUF-101 produced antinociceptive effects at lower doses than CBD, indicating that the addition of fluoride improved its pharmacological profile. Furthermore, some of the antinociceptive effects of CBD and HUF-101 effects seem to involve the activation of CB₁ and CB₂ receptors.

A robust variant of block Jacobi-Davidson for extracting a large number of eigenpairs: Application to grid-based real-space density functional theory

In this work, we investigate a block Jacobi-Davidson (J-D) variant suitable for sparse symmetric eigenproblems where a substantial number of extremal eigenvalues are desired (e.g., ground-state real-space quantum chemistry). Most J-D algorithm variations tend to slow down as the number of desired eigenpairs increases due to frequent orthogonalization against a growing list of solved eigenvectors. In our specification of block J-D, all of the steps of the algorithm are performed in clusters, including the linear solves, which allows us to greatly reduce computational effort with blocked matrix-vector multiplies. In addition, we move orthogonalization against locked eigenvectors and working eigenvectors outside of the inner loop but retain the single Ritz vector projection corresponding to the index of the correction vector. Furthermore, we minimize the computational effort by constraining the working subspace to the current vectors being updated and the latest set of corresponding correction vectors. Finally, we incorporate accuracy thresholds based on the precision required by the Fermi-Dirac distribution. The net result is a significant reduction in the computational effort against most previous block J-D implementations, especially as the number of wanted eigenpairs grows. We compare our approach with another robust implementation of block J-D (JDQMR) and the state-of-the-art Chebyshev filter subspace (CheFSI) method for various real-space density functional theory systems. Versus CheFSI, for first-row elements, our method yields competitive timings for valence-only systems and 4-6× speedups for all-electron systems with up to 10× reduced matrix-vector multiplies. For all-electron calculations on larger elements (e.g., gold) where the wanted spectrum is quite narrow compared to the full spectrum, we observe 60× speedup with 200× fewer matrix-vector multiples vs. CheFSI.

Classic IL-6R signalling is dispensable for intestinal epithelial proliferation and repair

Inflammatory bowel disease is characterized by disturbed cytokine signalling in the mucosa. Inhibition of the proinflammatory interleukin (IL)-6 pathway is a promising new therapeutic strategy, but safety concerns arise as IL-6 signalling also contributes to epithelial repair of the intestinal mucosa. To which extent IL-6 classic or trans-signalling contributes to intestinal repair remains elusive. We tested the influence of IL-6 classic signalling on intestinal repair and proliferation. Whereas IL-6 induced STAT3 phosphorylation in the colonic cancer cell lines, primary non-malignant intestinal organoids did not respond to IL-6 classic signalling. Mice deficient in intestinal IL-6R (IL-6R^ΔIEC mice) did not display increased susceptibility to acute dextran sulfate sodium (DSS)-induced colitis. In the azoxymethane DSS model IL-6R^ΔIEC mice were not protected from inflammation-induced carcinogenesis but showed comparable tumor load to wild-type mice. These data indicate that classic signalling is not the major pathway to transduce IL-6 stimuli into the intestinal epithelium.

Fluorinated Cannabidiol Derivatives: Enhancement of Activity in Mice Models Predictive of Anxiolytic, Antidepressant and Antipsychotic Effects

Cannabidiol (CBD) is a major Cannabis sativa constituent, which does not cause the typical marijuana psychoactivity. However, it has been shown to be active in a numerous pharmacological assays, including mice tests for anxiety, obsessive-compulsive disorder, depression and schizophrenia. In human trials the doses of CBD needed to achieve effects in anxiety and schizophrenia are high. We report now the synthesis of 3 fluorinated CBD derivatives, one of which, 4'-F-CBD (HUF-101) (1), is considerably more potent than CBD in behavioral assays in mice predictive of anxiolytic, antidepressant, antipsychotic and anti-compulsive activity. Similar to CBD, the anti-compulsive effects of HUF-101 depend on cannabinoid receptors.

Cannabidiol, a Major Non-Psychotropic Cannabis Constituent Enhances Fracture Healing and Stimulates Lysyl Hydroxylase Activity in Osteoblasts

Cannabinoid ligands regulate bone mass, but skeletal effects of cannabis (marijuana and hashish) have not been reported. Bone fractures are highly prevalent, involving prolonged immobilization and discomfort. Here we report that the major non-psychoactive cannabis constituent, cannabidiol (CBD), enhances the biomechanical properties of healing rat mid-femoral fractures. The maximal load and work-to-failure, but not the stiffness, of femurs from rats given a mixture of CBD and Δ(9) -tetrahydrocannabinol (THC) for 8 weeks were markedly increased by CBD. This effect is not shared by THC (the psychoactive component of cannabis), but THC potentiates the CBD stimulated work-to-failure at 6 weeks postfracture followed by attenuation of the CBD effect at 8 weeks. Using micro-computed tomography (μCT), the fracture callus size was transiently reduced by either CBD or THC 4 weeks after fracture but reached control level after 6 and 8 weeks. The callus material density was unaffected by CBD and/or THC. By contrast, CBD stimulated mRNA expression of Plod1 in primary osteoblast cultures, encoding an enzyme that catalyzes lysine hydroxylation, which is in turn involved in collagen crosslinking and stabilization. Using Fourier transform infrared (FTIR) spectroscopy we confirmed the increase in collagen crosslink ratio by CBD, which is likely to contribute to the improved biomechanical properties of the fracture callus. Taken together, these data show that CBD leads to improvement in fracture healing and demonstrate the critical mechanical role of collagen crosslinking enzymes.

Effect of the synthetic cannabinoid HU-210 on quorum sensing and on the production of quorum sensing-mediated virulence factors by Vibrio harveyi

Background

Bacterial populations communicate through the cell density-dependent mechanism of quorum sensing (QS). Vibrio harveyi, one of the best studied model organisms for QS, was used to explore effects of the synthetic cannabinoid HU-210 on QS and different QS-regulated physiological processes in bacteria.

Results

Analysis of QS-regulated bioluminescence in wild-type and mutant strains of V. harveyi revealed that HU-210 affects the autoinducer-2 (AI-2) pathway, one of three known QS cascades of V. harveyi. Furthermore, QS-mediated biofilm formation and swimming motility in the mutant strain BB152 (AI-1⁻, AI-2⁺) were significantly reduced in the presence of HU-210. HU-210 inhibited QS-mediated virulence factor production without any inhibitory effect on bacterial growth. It also alters the expression of several genes, which are regulated by QS, specifically downregulating the genes of the AI-2 QS cascade.

Conclusion

First evidence is being provided for interference of bacterial signal-transduction systems by a synthetic cannabinoid. The effect of HU-210 was specific to the AI-2 cascade in V. harveyi. AI-2 is known as a "universal autoinducer" and interference with its activity opens a broad spectrum of applications for synthetic cannabinoids in future research as a potential anti-QS agent.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-015-0499-0) contains supplementary material, which is available to authorized users.

PADMA-28, a traditional tibetan herbal preparation inhibits the respiratory burst in human neutrophils, the killing of epithelial cells by mixtures of oxidants and pro-inflammatory agonists and peroxidation of lipids

Both aqueous and methanolic fractions derived from the Tibetan preparation PADMA-28 (a mixture of 22 plants) used as an anti-atherosclerotic agent, and which is non-cytolytic to a variety of mammalian cells, were found to strongly inhibit (1) the killing of epithelial cells in culture induced by 'cocktails' comprising oxidants, membrane perforating agents and proteinases; (2) the generation of luminol-dependent chemiluminescence in human neutrophils stimulated by opsonized bacteria; (3) the peroxidation of intralipid (a preparation rich in phopholipids) induced in the presence of copper; and (4) the activity of neutrophil elastase. It is proposed that PADMA-28 might prove beneficial for the prevention of cell damage induced by synergism among pro-inflammatory agonists which is central in the initiation of tissue destruction in inflammatory and infectious conditions.

Peripheral, but not central effects of cannabidiol derivatives: mediation by CB(1) and unidentified receptors

Delta-9 tetrahydrocannabinol (Delta(9)-THC) and (-)-cannabidiol ((-)-CBD) are major constituents of the Cannabis sativa plant with different pharmacological profiles: (Delta(9)-THC activates cannabinoid CB(1) and CB(2) receptors and induces psychoactive and peripheral effects. (-)-CBD possesses no, or very weak affinity for these receptors. We tested a series of (+)- and (-)-CBD derivatives for central and peripheral effects in mice. None of the (-)-CBD derivatives were centrally active, yet most inhibited intestinal motility. Of the five (+)-CBD derivatives, all with CB(1) receptor affinity, only (+)-7-OH-CBD-DMH (DMH=1,1-dimethylheptyl), acted centrally, while all five arrested defecation. The effects of (+)-CBD-DMH and (+)-7-OH-CBD-DMH were inhibited by the CB(1) receptor antagonist SR141716. The CB(2) receptor antagonist SR144528, and the vanilloid TRPV1 receptor antagonist capsazepine, had no influence. Further, the (-)-CBD derivatives (-)-7-COOH-CBD and (-)-7-COOH-CBD-DMH, displayed antiinflammatory activity. We suggest that (+)-CBD analogues have mixed agonist/antagonist activity in the brain. Second, (-)-CBD analogues which are devoid of cannabinoid receptor affinity but which inhibit intestinal motility, suggest the existence of a non-CB(1), non-CB(2) receptor. Therefore, such analogues should be further developed as antidiarrheal and/or antiinflammatory drugs. We propose to study the therapeutic potential of (-)- and (+)-CBD derivatives for complex conditions such as inflammatory bowel disease and cystic fibrosis.

Enantiomeric cannabidiol derivatives: synthesis and binding to cannabinoid receptors

(-)-Cannabidiol (CBD) is a major, non psychotropic constituent of cannabis. It has been shown to cause numerous physiological effects of therapeutic importance. We have reported that CBD derivatives in both enantiomeric series are of pharmaceutical interest. Here we describe the syntheses of the major CBD metabolites, (-)-7-hydroxy-CBD and (-)-CBD-7-oic acid and their dimethylheptyl (DMH) homologs, as well as of the corresponding compounds in the enantiomeric (+)-CBD series. The starting materials were the respective CBD enantiomers and their DMH homologs. The binding of these compounds to the CB(1) and CB(2) cannabinoid receptors are compared. Surprisingly, contrary to the compounds in the (-) series, which do not bind to the receptors, most of the derivatives in the (+) series bind to the CB(1) receptor in the low nanomole range. Some of these compounds also bind weakly to the CB(2) receptor.

(+)-Cannabidiol analogues which bind cannabinoid receptors but exert peripheral activity only

Delta9-Tetrahydrocannabinol (Delta9-THC) and (-)-cannabidiol are major constituents of the Cannabis sativa plant with different pharmacological profiles: (-)-Delta9-tetrahydrocannabinol, but not (-)-cannabidiol, activates cannabinoid CB1 and CB2 receptors and induces psychoactive and peripheral effects. We have tested a series of (+)-cannabidiol derivatives, namely, (+)-cannabidiol-DMH (DMH-1,1-dimethylheptyl-), (+)-7-OH-cannabidiol-DMH, (+)-7-OH- cannabidiol, (+)-7-COOH- cannabidiol and (+)-7-COOH-cannabidiol-DMH, for central and peripheral (intestinal, antiinflammatory and peripheral pain) effects in mice. Although all (+)-cannabidiols bind to cannabinoid CB1 and CB2 receptors, only (+)-7-OH-cannabidiol-DMH was centrally active, while all (+)-cannabidiol analogues completely arrested defecation. The effects of (+)-cannabidiol-DMH and (+)-7-OH-cannabidiol-DMH were partially antagonized by the cannabinoid CB1 receptor antagonist N-(piperidiny-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (SR141716), but not by the cannabinoid CB2 receptor antagonist N-[-(1S)-endo-1,3,3-trimethil bicyclo [2.2.1] heptan-2-yl-5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)-pyrazole-3-carboxamide (SR144528), and had no effect on CB1(-/-) receptor knockout mice. (+)-Cannabidiol-DMH inhibited the peripheral pain response and arachidonic-acid-induced inflammation of the ear. We conclude that centrally inactive (+)-cannabidiol analogues should be further developed as antidiarrheal, antiinflammatory and analgesic drugs for gastrointestinal and other peripheral conditions.

Very low doses of Δ8-THC increase food consumption and alter neurotransmitter levels following weight loss

We have investigated the effect of 0.001 mg/kg delta(8)-tetrahydrocannabinol (THC) on food consumption, cognitive function, and neurotransmitters in mice. Sabra mice were treated with vehicle, THC, or THC+CB1 antagonist (SR141716A). The mice were fed for 2.5 h a day for 9 or 50 days. In the 9-day schedule, THC-treated mice showed a 16% increase in food intake compared with controls (P<.001). This effect was reversed by the antagonist (P<.01). In the long-term schedule a 22% increase in intake (P<.05) was recorded. During the course of the 9- and 50-day experimental protocol, all mice lost about 20% and 10% of their original weight, respectively, to reach approximately the same weights, which were not significantly different between the different treatment groups. In addition, THC caused an increase in activity (P<.05). Cognitive function showed a tendency to improve (P<.06) in the THC-treated mice, which was reversed by the antagonist for Days 4 and 5 of the maze (P<.01, and P<.05, respectively). Significant decreases in dopamine and serotonin (5-HT) levels were found both in the hypothalamus (P<.01) and the hippocampus (P<.01, P<.05), respectively, while norepinephrine (NE) levels showed tendency to increase in both the hypothalamus and hippocampus. Delta(8)-THC increased food intake significantly more (P<.05) than did delta(9)-THC, while performance and activity were similar. Thus, delta(8)-THC (0.001 mg/kg) caused increased food consumption and tendency to improve cognitive function, without cannabimimetic side effects. Hence, a low dose of THC might be a potential therapeutic agent in the treatment of weight disorders.

Comparison of the enzymatic stability and intraocular pressure effects of 2-arachidonylglycerol and noladin ether, a novel putative endocannabinoid

PURPOSE

The endogenous cannabinoids N-arachidonylethanolamide (AEA) and 2-arachidonylglycerol (2-AG) are known to decrease intraocular pressure (IOP). Recently, a novel putative endogenous cannabinoid, noladin ether, was isolated in porcine and rat brains. In the present study, both the degradation of endogenous cannabinoids in ocular tissues and the effect on IOP of 2-AG and noladin ether were compared.

METHODS

The rates of enzymatic degradation for AEA, 2-AG, and noladin ether were determined in bovine cornea and iris-ciliary body homogenates. 2-AG and noladin ether were dissolved in either hydroxypropyl-beta-cyclodextrin (HP-beta-CD) or propylene glycol and administered unilaterally to the rabbit eye. IOPs were measured in the treated and untreated eyes. The CB1 receptor antagonist AM251 was administered topically 15 minutes before the cannabinoids to investigate whether CB1 receptors mediate the effect on IOP produced by 2-AG and noladin ether.

RESULTS

Noladin ether degraded more slowly than either 2-AG or AEA in the iris-ciliary body and cornea homogenates. The effect on IOP of 2-AG was biphasic (i.e., an initial increase in IOP followed by a reduction in the treated eye). Noladin ether decreased IOP immediately after topical administration, and no initial IOP increase was observed in the treated eye. The CB1 receptor antagonist AM251 (25 micro g) blocked the effect on IOP of noladin ether but did not affect the action of 2-AG.

CONCLUSIONS

Topical administration of the novel putative endogenous cannabinoid noladin ether decreased IOP in rabbits. This IOP reduction was most probably mediated through the CB1 receptor. The effect on IOP of noladin ether differed from those of the known endogenous cannabinoids AEA and 2-AG, probably because of its more stable chemical structure.

An endogenous cannabinoid (2-AG) is neuroprotective after brain injury

Traumatic brain injury triggers the accumulation of harmful mediators that may lead to secondary damage. Protective mechanisms to attenuate damage are also set in motion. 2-Arachidonoyl glycerol (2-AG) is an endogenous cannabinoid, identified both in the periphery and in the brain, but its physiological roles have been only partially clarified. Here we show that, after injury to the mouse brain, 2-AG may have a neuroprotective role in which the cannabinoid system is involved. After closed head injury (CHI) in mice, the level of endogenous 2-AG was significantly elevated. We administered synthetic 2-AG to mice after CHI and found significant reduction of brain oedema, better clinical recovery, reduced infarct volume and reduced hippocampal cell death compared with controls. When 2-AG was administered together with additional inactive 2-acyl-glycerols that are normally present in the brain, functional recovery was significantly enhanced. The beneficial effect of 2-AG was dose-dependently attenuated by SR-141761A, an antagonist of the CB1 cannabinoid receptor.

N-nitrososdimethylamine is activated in microsomes from hepatocytes to reactive metabolites which damage DNA of non-parenchymal cells in rat liver

The liver carcinogen N-nitrosodimethylamine (NDMA) has to be metabolically activated by specific cytochromes before it can react with cellular macromolecules (e.g. proteins or DNA). Although hepatocytes are believed to be responsible for this activation, the liver tumours originate mainly from non-parenchymal cells (NPC). To investigate their activation capacity we determined NDMA-demethylase activity in isolated microsomes from both liver cell types. The results demonstrate that only hepatocytes have activation capacity. Additional experiments were performed with hepatocytes and NPC using the single cell microgel electrophoresis assay (MGE). DNA damage appears in both cell types following in vivo exposure. Tested in vitro, however, the carcinogens induce DNA damages only in hepatocytes (the cells which activate these compounds). N-nitroso-hydroxymethyl-methylamine could be the responsible metabolite as it is stable enough to be transported from hepatocytes to NPC in an intact liver.

Evidence for activation of carcinogenic o-anisidine by prostaglandin H synthase: 32P-postlabelling analysis of DNA adduct formation

2-Methoxyaniline (o-anisidine) is a urinary bladder carcinogen in both mice and rats. Since the urinary bladder contains substantial peroxidase activity, we examined the ability of prostaglandin H synthase (PHS), a prominent enzyme in the urinary bladder, to activate this carcinogen to metabolites binding to macromolecules. Using [14C]-labeled o-anisidine, we observed substantial PHS-dependent binding of o-anisidine to protein, DNA and polydeoxyribonucleotides [poly(dX)]. This binding is inhibited by radical scavengers glutathione, ascorbate and NADH. The nuclease P1 and 1-butanol extraction enrichment procedure of the 32P-postlabeling analysis of DNA modified by activated o-anisidine provide evidence that covalent binding to DNA is the principal type of DNA modification. Deoxyguanosine is determined to be the major target for binding of o-anisidine in DNA. The possibility that o-anisidine is carcinogenic to the rodent urinary bladder via its activation by bladder PHS is suggested. The results presented here are the first report demonstrating a PHS-mediated activation of o-anisidine to reactive species forming covalent DNA adducts.

Evidence for reductive activation of carcinogenic aristolochic acids by prostaglandin H synthase -- (32)P-postlabeling analysis of DNA adduct formation

Aristolochic acid (AA), a naturally occurring nephrotoxin and carcinogen, is implicated in an unique type of renal fibrosis, designated Chinese herbs nephropathy (CHN), which can develop to urothelial cancer. Understanding which enzymes are involved in AA activation and/or detoxication is important in the assessment of an individual susceptibility to this natural carcinogen. We examined the ability of prostaglandin H synthase (PHS) to activate AA to metabolites forming DNA adducts with the nuclease P1 and 1-butanol extraction enrichment procedure of the (32)P-postlabeling assay. PHS is a prominent enzyme in the kidney and urothelial tissues. Ram seminal vesicle (RSV) microsomes, which contain high levels of PHS, generated AA-DNA adduct patterns reproducing those found in renal tissues in CHN patients. 7-(Deoxyadenosin-N(6)-yl)aristolactam I, 7-(deoxyguanosin-N(2)-yl)aristolactam I and 7-(deoxyadenosin-N(6)-yl)aristolactam II were identified as AA-DNA adducts formed by AAI. Two adducts, 7-(deoxyguanosin-N(2)-yl)aristolactam II and 7-(deoxyadenosin-N(6)-yl)aristolactam II, were generated from AAII. According to the structures of the DNA adducts identified, nitroreduction is the crucial pathway in the metabolic activation of AA. The identity of PHS as the activating enzyme in RSV microsomes was proven with different cofactors and inhibitors. Only indomethacin, a selective inhibitor of PHS, significantly decreased the amount of adducts formed by RSV microsomes. The inhibitor of NADPH:CYP reductase (alpha-lipoic acid) and some selective inhibitors of cytochromes P450 (CYP) were not effective. Likewise, only cofactors of PHS, arachidonic acid and hydrogen peroxide, supported the DNA adduct formation of AAI and AAII, while NADPH and NADH were ineffective. These results demonstrate a key role of PHS in the activation pathway of AAI and AAII in the RSV microsomal system and were corroborated with the purified enzyme, namely ovine PHS-1. The results presented here are the first report demonstrating a reductive activation of nitroaromatic compounds by PHS-1.

Critical role of the endogenous cannabinoid system in mouse pup suckling and growth

Delta9-tetrahydrocannabinol, the active principle in marijuana, is a cannabinoid receptor agonist. Both the crude drug and delta9-tetrahydrocannabinol have been used as appetite promoters. The endogenous cannabinoid, arachidonoyl ethanolamide (anandamide), likewise a cannabinoid receptor agonist, has been shown to have the same effect. In contrast, the cannabinoid CB1 receptor antagonist N-(piperidin-1-yl)-5(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1-H-pyrazole-3-carboxamide (SR141716A) reduces food intake. Here, we report that administration of SR141716A to newly born mouse pups (either a single administration on postnatal day 1, or daily for a week as of postnatal day 2) had a devastating effect on milk ingestion and growth. The first 24 h after birth appeared the most critical for the growth stunting effect of SR141716A. Death followed within 4-8 days. Co-administration of delta9-tetrahydrocannabinol almost fully reversed the effect of the antagonist in the week-long regimen. Co-administration of 2-arachidonoyl glycerol, an endocannabinoid, with 2-palmitoyl glycerol and 2-linoleoyl glycerol, which enhance 2-arachidonoyl glycerol potency, resulted in a significant delay in mortality rates caused by the antagonist. We conclude that the endocannabinoid system plays a vital role in milk suckling, and hence in growth and development during the early stages of mouse life.

2-arachidonyl glyceryl ether, an endogenous agonist of the cannabinoid CB1 receptor

Two types of endogenous cannabinoid-receptor agonists have been identified thus far. They are the ethanolamides of polyunsaturated fatty acids--arachidonoyl ethanolamide (anandamide) is the best known compound in the amide series--and 2-arachidonoyl glycerol, the only known endocannabinoid in the ester series. We report now an example of a third, ether-type endocannabinoid, 2-arachidonyl glyceryl ether (noladin ether), isolated from porcine brain. The structure of noladin ether was determined by mass spectrometry and nuclear magnetic resonance spectroscopy and was confirmed by comparison with a synthetic sample. It binds to the CB(1) cannabinoid receptor (K(i) = 21.2 +/- 0.5 nM) and causes sedation, hypothermia, intestinal immobility, and mild antinociception in mice. It binds weakly to the CB(2) receptor (K(i) > 3 microM).

2-Arachidonylglycerol, an endogenous cannabinoid, inhibits tumor necrosis factor-alpha production in murine macrophages, and in mice

2-Arachidonylglycerol (2-AG) inhibits the production in vitro of tumor necrosis factor-alpha (TNF-alpha) by mouse macrophages, as well as in mice. It has no effect on the production of nitric oxide (NO). The effect on TNF-alpha is enhanced when 2-AG is administered together with 2-linoleylglycerol (2-Lino-G) and 2-palmitylglycerol (2-PalmG), an 'entourage effect' previously noted in several behavioral and binding assays. 2-AG also suppresses the formation of radical oxygen intermediates.

HU-308: a specific agonist for CB(2), a peripheral cannabinoid receptor

Two cannabinoid receptors have been identified: CB(1), present in the central nervous system (CNS) and to a lesser extent in other tissues, and CB(2), present outside the CNS, in peripheral organs. There is evidence for the presence of CB(2)-like receptors in peripheral nerve terminals. We report now that we have synthesized a CB(2)-specific agonist, code-named HU-308. This cannabinoid does not bind to CB(1) (K(i) > 10 microM), but does so efficiently to CB(2) (K(i) = 22.7 +/- 3.9 nM); it inhibits forskolin-stimulated cyclic AMP production in CB(2)-transfected cells, but does so much less in CB(1)-transfected cells. HU-308 shows no activity in mice in a tetrad of behavioral tests, which together have been shown to be specific for tetrahydrocannabinol (THC)-type activity in the CNS mediated by CB(1). However, HU-308 reduces blood pressure, blocks defecation, and elicits anti-inflammatory and peripheral analgesic activity. The hypotension, the inhibition of defecation, the anti-inflammatory and peripheral analgesic effects produced by HU-308 are blocked (or partially blocked) by the CB(2) antagonist SR-144528, but not by the CB(1) antagonist SR-141716A. These results demonstrate the feasibility of discovering novel nonpsychotropic cannabinoids that may lead to new therapies for hypertension, inflammation, and pain.

Mechanisms of resistance to methotrexate in childhood acute lymphoblastic leukemia: circumvention of thymidylate synthase inhibition

PURPOSE

In about 25% of patients suffering from acute lymphoblastic leukemia (ALL) treatment failures occur that are most likely due to development of resistance to methotrexate (MTX). Blasts from patients with ALL were evaluated for MTX uptake, formation of long-chain MTX polyglutamates (MTX-Glu5+6), cytotoxicity and thymidylate synthase inhibition by MTX and compared to blasts from patients with acute myelogenous leukemia (AML).

METHODS

Radioactively labeled MTX-Glu(n) were analyzed by means of HPLC. Thymidylate synthase activity was measured by a tritium-release assay. Cytotoxicity was determined by trypan blue exclusion.

RESULTS

In most ALL blasts (n = 9) large amounts of MTX-Glu5+6 (1.06-7.03 pmol/10(7) cells) and high cytotoxicity (43.5% 92.7%) were found, while in others small amounts of MTX-Glu5+6 (0.0-0.39 pmol/10(7) cells) caused only weak cytotoxicity (6.0% 27.9%) (n = 5, 2 relapsed patients). Resistance to MTX in blasts from AML patients (n = 5) was also caused by reduced synthesis of MTX-Glu5s+6 (0.0-0.42 pmol/10(7) cells). In contrast, some ALL blasts (n = 7, 4 relapsed patients) were able to survive MTX treatment despite large amounts of MTX-Glu5+6 (1.5-5.05 pmol/10(7) cells) and extensive thymidylate synthase inhibition.

CONCLUSIONS

Since the majority of ALL patients were examined at first diagnosis, an inherent mechanism of resistance seems most likely. We propose a mechanism based on the switch of thymidylate synthesis to the salvage pathway.

Aristolactam I a metabolite of aristolochic acid I upon activation forms an adduct found in DNA of patients with Chinese herbs nephropathy

Aristolochic acid (AA) a naturally occuring nephrotoxin and carcinogen is implicated in a unique type of renal fibrosis, designated Chinese herbs nephropathy (CHN). We identified AA-specific DNA adducts in kidneys and in a ureter obtained from CHN patients after renal transplantation. AA is a plant extract of aristolochia species containing AA I as the major component. Aristolactams are the principal detoxication metabolites of AA, which were detected in urine and faeces from animals and humans. They are activated by cytochrome P450 (P450) and peroxidase to form DNA adducts. Using the 32P-postlabelling assay we investigated the formation of DNA adducts by aristolactam I in these two activation systems. A combination of two independent chromatographic systems (ion-exchange chromatography TLC and reversed-phase HPLC) with reference compounds was used for the identification of adducts. Aristolactam I activated by peroxidase led to the formation of several adducts. Two major adducts were identical to adducts previously observed in vivo. 7-(deoxyguanosin-N2-yl)aristolactam I (dG-AAI) and 7-(deoxyadenosin-N6-yl)aristolactam I (dA-AAI) were formed in DNA during the peroxidase-mediated one-electron oxidation of aristolactam I. Aristolactam I activated by P450 led to one major adduct and four minor ones. Beside the principal AA-DNA adducts identified recently in the ureter of one patient with CHN, an additional minor adduct was detected, which was found to have indistinguishable chromatographic properties on TLC and HPLC from the major adduct formed from aristolactam I by P450 activation. Thus, this minor AA-adduct might be evolved from the AAI detoxication metabolite (aristolactam I) by P450 activation. These results indicate a potential carcinogenic effect of aristolactam I in humans.

Analysis of the inhibition of N-nitroso-dimethylamine activation in the liver by N-nitro-dimethylamine using a new non-linear statistical method

N-nitro-dimethylamine (NTDMA) is carcinogenic to rats: it induces nasal cavity tumours. It can be demethylated to N-nitromethylamine and formaldehyde and reduced to N-nitroso-dimethylamine (NDMA): a potent liver carcinogen and also of the nasal cavity if activation in the liver is blocked. To explain the mechanism of NTDMA carcinogenicity we compared its demethylation with that of NDMA in liver microsomes from female and male rats, untreated, fasted or treated with ethanol to induce cytochrome P450 2E1 (CYP2E1). Kinetic parameters were analysed by nonlinear statistical methods, which yielded unbiased parameter estimates for the calculated Km and Vmax values. Km for both compounds was very similar in females (24-47 microM) whereas Vmax for NTDMA was consistently higher than for NDMA as substrate: 1.07-4.70 nmol formaldehyde/mg microsomal protein x min and 0.52-2.76 nmol, respectively. In liver microsomes from induced male rats NTDMA was found to be a much more effective inhibitor of NDMA activation (KEI 39.6-73.6 microM) than NDMA of NTDMA demethylation (KEI 224-286 microM). Nasal microsomes can demethylate both NDMA and NTDMA but the kinetics are vastly different. NTDMA is demethylated at a linear rate and approximately 10-fold more effectively than NDMA. The mechanism of carcinogenicity of ingested NTDMA, we propose, is a partial reduction to NDMA in the liver and inhibition of NDMA activation in the liver by residual NTDMA, which enables NDMA to reach the nasal mucosa where it is activated to DNA-alkylating species and the observed tumours are formed.

Cannabinol derivatives: binding to cannabinoid receptors and inhibition of adenylylcyclase

Several derivatives of cannabinol and the 1,1-dimethylheptyl homolog (DMH) of cannabinol were prepared and assayed for binding to the brain and the peripheral cannabinoid receptors (CB1 and CB2), as well as for activation of CB1- and CB2-mediated inhibition of adenylylcyclase. The DMH derivatives were much more potent than the pentyl (i.e., cannabinol) derivatives. 11-Hydroxycannabinol (4a) was found to bind potently to both CB1 and CB2 (Ki values of 38.0 +/- 7.2 and 26.6 +/- 5.5 nM, respectively) and to inhibit CB1-mediated adenylylcyclase with an EC50 of 58.1 +/- 6.2 nM but to cause only 20% inhibition of CB2-mediated adenylylcyclase at 10 microM. It behaves as a specific, though not potent, CB2 antagonist. 11-Hydroxycannabinol-DMH (4b) is a very potent agonist for both CB1 and CB2 (Ki values of 100 +/- 50 and 200 +/- 40 pM; EC50 of adenylylcyclase inhibition 56.2 +/- 4.2 and 207.5 +/- 27.8 pM, respectively).

(-)-Delta9-tetrahydrocannabinol antagonizes the peripheral cannabinoid receptor-mediated inhibition of adenylyl cyclase

(-)-Delta9-Tetrahydrocannabinol ((-)-Delta9-THC) is the major active psychotropic component of the marijuana plant, Cannabis sativa. The membrane proteins that have been found to bind this material or its derivatives have been called the cannabinoid receptors. Two GTP-binding protein-coupled cannabinoid receptors have been cloned. CB1 or the neuronal cannabinoid receptor is found mostly in neuronal cells and tissues while CB2 or the peripheral cannabinoid receptor has been detected in spleen and in several cells of the immune system. It has previously been shown that activation of CB1 or CB2 receptors by cannabinoid agonists inhibits adenylyl cyclase activity. Utilizing Chinese hamster ovary cells and COS cells transfected with the cannabinoid receptors we report that (-)-Delta9-THC binds to both receptors with similar affinity. However, in contrast to its capacity to serve as an agonist for the CB1 receptor, (-)-Delta9-THC was only able to induce a very slight inhibition of adenylyl cyclase at the CB2 receptor. Morever, (-)-Delta9-THC antagonizes the agonist-induced inhibition of adenylyl cyclase mediated by CB2. Therefore, we conclude that (-)-Delta9-THC constitutes a weak antagonist for the CB2 receptor.

Suppression of experimental autoimmune encephalomyelitis by cannabinoids

The effect of delta 8-THC on experimental autoimmune encephalomyelitis (EAE) was examined. delta 8-THC is an analogue of delta 9-THC, the psychoactive component of marijuana. It is more stable and less psychotropic than delta 9-THC and like the latter it binds to the brain cannabinoid receptor. Two strains of rats were inoculated for EAE, and delta 8-THC (40 mg/kg) was administered for up to 21 days. delta 8-THC significantly reduced the incidence and severity of neurological deficit in both rat strains. The beneficial influence of delta 8-THC only occurred on oral administration and not with parenteral injection. Serum corticosterone levels were twofold elevated in rats with EAE chronically treated with delta 8-THC. These results suggest that suppression of EAE by cannabinoids may be related to their effect on corticosterone secretion.

Anxiolytic effect of cannabidiol derivatives in the elevated plus-maze

1. In order to assess the presence of anxiolytic properties in cannabidiol (CBD) derivatives HU-219, HU-252 and HU-261, these drugs were tested in rats submitted to the elevated plus-maze model of anxiety. 2. Additional groups received diazepam or CBD. HU-219 (0.03-1 mg/kg) and CBD (5 mg/kg) significantly increased the percentage of open arm entries without changing the total number of entries, an anxiolytic-like effect. 3. Both HU-252 and HU-261 increased the percentage of time spent in open arms and the total number of entries, but only at the dose of 1 mg/kg. 4. Diazepam (2.5 mg/kg) increased both the percentage of entries and time spent on open arms and the total number of entries. 5. The results confirm previous findings with CBD and indicate that its derivative HU-219 may possess a similar anxiolytic-like profile. 6. Results from HU-252 and HU-261 are less apparent and suggest that the compounds may increase general exploratory activity in a limited range of doses.

Discriminative stimulus effects and receptor binding of enantiomeric pairs of cannabinoids in rats and pigeons; a comparison

The cannabimimetic activity of two enantiomeric pairs of compounds structurally different from the classical cannabinoids was evaluated in rats and pigeons, trained to discriminate between the presence and absence of (-)-delta-9-tetrahydrocannabinol (THC). One pair of enantiomers [compounds (+)-HU-249 and (-)-HU-250] has a 5-membered oxygen-containing benzofuran ring; the second pair [(+)-HU-253 and (-)-HU-254] does not have an oxygen-containing ring. The onset of cannabimimetic activity was slower, and duration of action was longer for the test compounds than for THC. HU-250 exhibited cannabimimetic activity with a potency similar to THC in both species; HU-249 was 22 times less active than THC. The pattern of response rate and THC-like responding obtained with HU-249 were dissociated; THC-like responding occurred during the later test intervals when suppression of response rate was reduced. HU-250 bound to the cannabinoid receptor with a Ki of 47.6 nM, essentially identical to that of THC. HU-249 was much less active, with a Ki of 28.3 microM. The triacetate enantiomers, HU-253 and HU-254, occasioned THC-like responding in both species, HU-254 being about 4.5 times less potent than THC and 3 to 4 times more potent than HU-253. In binding, HU-253 was also less potent than HU-254. The corresponding triols were considerably more potent than the acetates; (-)-HU-256 had a Ki of 198 nM, whereas (+)-HU-255 had a Ki of 43.8 nM, comparable to that of THC.

Isolation and structure of a brain constituent that binds to the cannabinoid receptor

Arachidonylethanolamide, an arachidonic acid derivative in porcine brain, was identified in a screen for endogenous ligands for the cannabinoid receptor. The structure of this compound, which has been named "anandamide," was determined by mass spectrometry and nuclear magnetic resonance spectroscopy and was confirmed by synthesis. Anandamide inhibited the specific binding of a radiolabeled cannabinoid probe to synaptosomal membranes in a manner typical of competitive ligands and produced a concentration-dependent inhibition of the electrically evoked twitch response to the mouse vas deferens, a characteristic effect of psychotropic cannabinoids. These properties suggest that anandamide may function as a natural ligand for the cannabinoid receptor.

Synthetic nonpsychotropic cannabinoids with potent antiinflammatory, analgesic, and leukocyte antiadhesion activities

Two strategies for the design of therapeutically useful cannabinoids have been combined to produce compounds with greatly increased antiinflammatory activity and with a low potential for adverse side effects. Enantiomeric cannabinoids with a carboxylic acid group at position 7 and with an elongated and branched alkyl sidechain at position 5' have been synthesized and tested for antiinflammatory activity. They were effective when given orally at doses of 10 micrograms/kg in reducing paw edema in mice that had been induced by either arachidonic acid or platelet activating factor. Leukocyte adhesion to culture dishes was also reduced in peritoneal cells from mice in which the cannabinoids were orally administered in the same dose range as for the paw edema tests. Antinociception could be observed in the mouse hot plate assay; however, little stereochemical preference was seen in contrast to the above tests where the 3R,4R compounds are more active than the 3S,4S enantiomers. Finally, in agreement with earlier reports on the naturally occurring pentyl side chain acids, the synthetic acids showed little activity in producing catalepsy in the mouse, suggesting that they would be nonpsychotropic in humans.

A novel probe for the cannabinoid receptor

The 1,1-dimethylheptyl (DMH) homologue of 7-hydroxy-delta 6-tetrahydrocannabinol (3) is the most potent cannabimimetic substance reported so far. Hydrogenation of 3 leads to a mixture of the epimers of 5'-(1,1-dimethylheptyl)-7-hydroxyhexahydrocannabinol or to either the equatorial (7) or to the axial epimer (8), depending on the catalysts and conditions used. Compound 7 discriminates for delta 1-THC (2) in pigeons (ED50 = 0.002 mg/kg, after 4.5 h), at the potency level of 3, and binds to the cannabinoid receptor with a KD of 45 pM, considerably lower than the Ki of 180 pM measured for compound 3 and the Ki of 2.0 nM measured for CP-55940 (1), a widely employed ligand. Tritiated 7 was used as a novel probe for the cannabinoid receptor.

A random walk through a cannabis field

The present overview covers various aspects of research going on in the Cannabis field in the Department of Natural Products at the Hebrew University. In the first part we discuss, and try to explain, the reason for the absence of the term Cannabis (and possibly also opium) in the Old Testament. In the second part we bring evidence that, contrary to widely held views, stereospecificity of cannabinoid action is extremely high, and in certain cases almost absolute. Previous results seem to have been due to impurities in the samples tested. (+)-Delta-1-THC, (+)-delta-6-THC and (+)-7-hydroxy-delta-6-THC, when purified sufficiently, exhibit activity of about 1% of that of the natural (-) enantiomers. A new labelled cannabinoid ligand has been prepared by catalytic reduction of (-)-7-hydroxy-delta-6-THC dimethylheptyl. The equatorial C-1 epimer obtained binds to the cannabinoid receptor with a KI of 40 pM. This compound is one of the most active cannabinoids tested so far for binding to the canabinoid receptor, and may become an important tool in cannabinoid research.

Cannabimimetic activity of novel enantiomeric, benzofuran cannabinoids

The synthesis of the (2R,3R,4S,6R)-7/(2S,3S,4R,6S)-8 enantiomeric pair of benzofuran cannabinoids is reported together with the 1H and 13C NMR spectral parameters. In benzofuran 8 the configurational arrangement of ligated groups at the stereogenic C(3) atom (through which the terpene moiety is connected to the aromatic ring) is very similar to that of the corresponding atom in natural (3R,4R)-delta 1-tetrahydrocannabinol (delta 1-THC), although their respective Cahn-Ingold-Prelog descriptors are different. In drug-discrimination tests in pigeons and rats, benzofuran 8 is as active as delta 1-THC; in the mouse ring test compound 8 is more active than delta 6-THC. Enantiomer 7 is considerably less active than enantiomer 8 in both tests. These results can be explained by the fact that both 7 and 8 have a dimethylheptyl side chain (which is known to enhance cannabimimetic activity) and that delta 1-THC and benzofuran 8 have closely related conformations, as determined by molecular mechanics.