Assessment of driving capability through the use of clinical and psychomotor tests in relation to blood cannabinoids levels following oral administration of 20 mg dronabinol or of a cannabis decoction made with 20 or 60 mg Delta9-THC.

Delta(9)-Tetrahydrocannabinol (THC) is frequently found in the blood of drivers suspected of driving under the influence of cannabis or involved in traffic crashes. The present study used a double-blind crossover design to compare the effects of medium (16.5 mg THC) and high doses (45.7 mg THC) of hemp milk decoctions or of a medium dose of dronabinol (20 mg synthetic THC, Marinol on several skills required for safe driving. Forensic interpretation of cannabinoids blood concentrations were attempted using the models proposed by Daldrup (cannabis influencing factor or CIF) and Huestis and coworkers. First, the time concentration-profiles of THC, 11-hydroxy-Delta(9)-tetrahydrocannabinol (11-OH-THC) (active metabolite of THC), and 11-nor-9-carboxy-Delta(9)-tetrahydrocannabinol (THCCOOH) in whole blood were determined by gas chromatography-mass spectrometry-negative ion chemical ionization. Compared to smoking studies, relatively low concentrations were measured in blood. The highest mean THC concentration (8.4 ng/mL) was achieved 1 h after ingestion of the strongest decoction. Mean maximum 11-OH-THC level (12.3 ng/mL) slightly exceeded that of THC. THCCOOH reached its highest mean concentration (66.2 ng/mL) 2.5-5.5 h after intake. Individual blood levels showed considerable intersubject variability. The willingness to drive was influenced by the importance of the requested task. Under significant cannabinoids influence, the participants refused to drive when they were asked whether they would agree to accomplish several unimportant tasks, (e.g., driving a friend to a party). Most of the participants reported a significant feeling of intoxication and did not appreciate the effects, notably those felt after drinking the strongest decoction. Road sign and tracking testing revealed obvious and statistically significant differences between placebo and treatments. A marked impairment was detected after ingestion of the strongest decoction. A CIF value, which relies on the molar ratio of main active to inactive cannabinoids, greater than 10 was found to correlate with a strong feeling of intoxication. It also matched with a significant decrease in the willingness to drive, and it matched also with a significant impairment in tracking performances. The mathematic model II proposed by Huestis et al. (1992) provided at best a rough estimate of the time of oral administration with 27% of actual values being out of range of the 95% confidence interval. The sum of THC and 11-OH-THC blood concentrations provided a better estimate of impairment than THC alone. This controlled clinical study points out the negative influence on fitness to drive after medium or high dose oral THC or dronabinol.

Effets motivationnels des cannabinoïdes dans un modèle animal de la schizophrénie

Depuis quelques décennies, la consommation de cannabis et son usage thérapeutique sont le sujet de nombreux débats. Le cannabis est la drogue illicite la plus consommée au monde et cette consommation se trouve dix fois plus élevée chez les patients atteints de schizophrénie que dans la population générale. L’hypothèse d’une automédication initialement proposée afin d’expliquer la consommation élevée de cannabis chez les patients atteints de schizophrénie est maintenant remise en question. En effet, les rapports indiquant une aggravation des symptômes plutôt qu’une amélioration suite à une consommation à long terme sont de plus en plus nombreux. Sachant que le cannabis peut induire des effets soit plaisants soit aversifs, la question se pose à savoir si une prédominance de la valence motivationnelle positive ou une diminution de la valence négative du cannabis peut expliquer la consommation élevée parmi les individus ayant un diagnostic de schizophrénie? Bien qu’un grand nombre de recherches pré-cliniques aient été menées chez l’animal normal pour évaluer l’effet motivationnel du Δ9-tétrahydrocannabinol (THC) et autres cannabinoïdes synthétiques, aucune n’a abordé cette problématique dans un modèle animal de la schizophrénie. Cette lacune nous a donc amené à étudier la valence motivationnelle du THC et de l’agoniste cannabinoïde WIN55,212-2 (WIN) dans un modèle animal de la schizophrénie: la lésion néonatale de l’hippocampe ventral (NVHL). Dans le premier article, nous présentons les résultats de quatre expériences. Une première avait pour objectif de déterminer si la procédure expérimentale que nous avons utilisée permettait de reproduire des signes distinctifs du modèle animal de la schizophrénie. Par la suite, nous avons évalué i) l’effet d’une dose de WIN sur l’activité locomotrice spontanée et ii) la valence motivationnelle du THC (0.5 mg/kg, i.p) et du WIN (1 mg/kg, i.p) chez les rats adolescents (jour post-natal 28-40, PD28-40) et adultes (PD56) au moyen du paradigme de préférence de place conditionnée (PPC). Tel qu’attendu, la réponse locomotrice à l’amphétamine (0.75 et 1.5 mg/kg) chez les rats NVHL adultes était supérieure à celle des rats contrôles (test distinctif du modèle). Le THC a induit une tendance aversive chez les rats contrôles adultes. Enfin, le WIN a stimulé l’activité locomotrice et induit une aversion significative chez les rats adultes NVHL. Dans un deuxième article, nous avons évalué la valence motivationnelle du THC (0.5 mg/kg), du WIN (1 et 3 mg/kg) et l’effet de l’amphétamine au moyen du paradigme d’autostimulation électrique intracérébrale (ASI). Les résultats montrent que : i) l’effet amplificateur de l’amphétamine sur l’ASI était de plus courte durée chez les rats NVHL; ii) le THC produit une légère atténuation de la récompense chez les rats contrôles tandis que le WIN a produit une atténuation plus prononcée de la récompense chez les rats NVHL, un effet qui a été bloqué par l’antagoniste aux récepteurs CB1, le AM251 (3 mg/kg). Pour la première fois les résultats suggèrent une altération du système endocannabinoïde dans un modèle animal de la schizophrénie. Ils indiquent qu’une exposition aigüe conduit à une prédominance de la valence négative. Bien qu’en apparente contradiction avec les études cliniques, ces résultats soulignent l’importance du contexte socio-environnemental pour expliquer les effets du cannabis chez les patients. De plus ils encouragent les futures études à évaluer cette valence sur un modèle d’exposition chronique.

Consumo de sustancias y noxas prenatales en madres de pacientes con síndrome de Möbius y Möbius Like

Introducción: El síndrome de Möbius y Möbius Like es una entidad poco frecuente caracterizada principalmente por parálisis congénita del VI y VII par craneal. Su etiología es poco conocida aunque se ha asociado a inductores del aborto. El objetivo de este estudio es describir factores anómalos, tóxicos o nocivos que hayan estado presentes en el embarazo de las madres de estos pacientes. Metodología: se realizó una encuesta auto-diligenciable a 15 madres de pacientes con el diagnóstico, indagando sobre condiciones anómalas y/o exposicionales del embarazo, el padre y el ambiente. Resultados: Las madres se encontraban entre los 16 y 34 años al momento de quedar embarazadas, en su mayoría eran solteras, estudiantes y sin planes de embarazo. Once en total usaron algún medicamento y/o sustancias durante la gestación; seis de ellas Misoprostol (40%). Las otras sustancias utilizadas incluyeron: alternativas, cigarrillo, alcohol, ibuprofeno, anticonceptivos, otros. Como anomalías del periodo prenatal se reportaron sangrado activo y/o amenaza de aborto, infección, exposición a químicos ambientales y enfermedad materna activa. Las condiciones paternas descritas fueron alcoholismo y/o drogadicción, enfermedad y edad ≥ 40 años en bajo porcentaje. Conclusión: El síndrome de Möbius y Möbius Like es una patología poco frecuente de la cual aún se debe seguir investigando sobre su etiología, para plantear posibles medidas de prevención.

A novel component of cannabis extract potentiates excitatory synaptic transmission in rat olfactory cortex in vitro

Cannabis is a potential treatment for epilepsy, although the few human studies supporting this use have proved inconclusive. Previously, we showed that a standardized cannabis extract (SCE), isolated Delta(9)-tetrahydrocannabinol (Delta(9)-THC), and even Delta(9)-THC-free SCE inhibited muscarinic agonist-induced epileptiform bursting in rat olfactory cortical brain slices, acting via CB1 receptors. The present work demonstrates that although Delta(9)-THC (1microM) significantly depressed evoked depolarizing postsynaptic potentials (PSPs) in rat olfactory cortex neurones, both SCE and Delta(9)-THC-free SCE significantly potentiated evoked PSPs (all results were fully reversed by the CB1 receptor antagonist SR141716A, 1microM); interestingly, the potentiation by Delta(9)-THC-free SCE was greater than that produced by SCE. On comparing the effects of Delta(9)-THC-free SCE upon evoked PSPs and artificial PSPs (aPSPs; evoked electrotonically following brief intracellular current injection), PSPs were enhanced, whereas aPSPs were unaffected, suggesting that the effect was not due to changes in background input resistance. Similar recordings made using CB1 receptor-deficient knockout mice (CB1(-/-)) and wild-type littermate controls revealed cannabinoid or extract-induced changes in membrane resistance, cell excitability and synaptic transmission in wild-type mice that were similar to those seen in rat neurones, but no effect on these properties were seen in CB1(-/-) cells. It appears that the unknown extract constituent(s) effects over-rode the suppressive effects of Delta(9)-THC on excitatory neurotransmitter release, which may explain some patients' preference for herbal cannabis rather than isolated Delta(9)-THC (due to attenuation of some of the central Delta(9)-THC side effects) and possibly account for the rare incidence of seizures in some individuals taking cannabis recreationally

Cannabinoids inhibit human keratinocyte proliferation through a non-CB1/CB2 mechanism and have a potential therapeutic value in the treatment of psoriasis

Background: Cannabinoids from cannabis (Cannabis sativa) are anti-inflammatory and have inhibitory effects on the proliferation of a number of tumorigenic cell lines, some of which are mediated via cannabinoid receptors. Cannabinoid (CB) receptors are present in human skin and anandamide, an endogenous CB receptor ligand, inhibits epidermal keratinocyte differentiation. Psoriasis is an inflammatory disease also characterised in part by epidermal keratinocyte hyper-proliferation. Objective: We investigated the plant cannabinoids Delta-9 tetrahydrocannabinol, cannabidiol, cannabinol and cannabigerol for their ability to inhibit the proliferation of a hyper-proliferating human keratinocyte cell line and for any involvement of cannabinoid receptors. Methods: A keratinocyte proliferation assay was used to assess the effect of treatment with cannabinoids. Cell integrity and metabolic competence confirmed using lactate-dehydrogenase and adenosine tri-phosphate assays. To determine the involvement of the receptors, specific agonist and antagonist were used in conjunction with some phytocannabinoids. Western blot and RT-PCR analysis confirmed presence of CB1 and CB2 receptors. Results: The cannabinoids tested all inhibited keratinocyte proliferation in a concentration-dependent manner. The selective CB2 receptor agonists JWH015 and BML190 elicited only partial inhibition, the non-selective CB agonist HU210 produced a concentration-dependent response, the activity of theses agonists were not blocked by either C81 /C82 antagonists. Conclusion: The results indicate that while CB receptors may have a circumstantial role in keratinocyte proliferation, they do not contribute significantly to this process. Our results show that cannabinoids inhibit keratinocyte proliferation, and therefore support a potential role for cannabinoids in the treatment of psoriasis. (c) 2006 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

Cannabidiol, a Cannabis sativa constituent, as an anxiolytic drug

Objectives: To review and describe studies of the non-psychotomimetic constituent of Cannabis sativa, cannabidiol (CBD), as an anxiolytic drug and discuss its possible mechanisms of action. Method: The articles selected for the review were identified through searches in English,articles, and book chapters were handsearched for additional references. Experimental animal and human studies were included, with no time restraints. Results: Studies using animal models of anxiety and involving healthy volunteers clearly suggest an anxiolytic-like effect of CBD. like", and "cannabidiol and anxiety". The reference lists of the publications included, review Portuguese, and Spanish in the electronic databases ISI Web of Knowledge, SciELO, PubMed, and PsycINFO, combining the search terms "cannabidiol and anxiolytic", "cannabidiol and anxiolytic-articles, and book chapters were handsearched for additional references. Experimental animal and human studies were included, with no time restraints. Results: Studies using animal models of anxiety and involving healthy volunteers clearly suggest an anxiolytic-like effect of CBD. Moreover, CBD was shown to reduce anxiety in patients with social anxiety disorder. Conclusion: like", and "cannabidiol and anxiety". The reference lists of the publications included, review Future clinical trials involving patients with different anxiety disorders are warranted, especially of panic disorder, obsessive-compulsive disorder, social anxiety disorder, and post-traumatic stress disorders. The adequate therapeutic window of CBD and the precise mechanisms involved in its anxiolytic action remain to be determined.

Phytocannabinoids beyond the Cannabis plant - do they exist?

It is intriguing that during human cultural evolution man has detected plant natural products that appear to target key protein receptors of important physiological systems rather selectively. Plants containing such secondary metabolites usually belong to unique chemotaxa, induce potent pharmacological effects and have typically been used for recreational and medicinal purposes or as poisons. Cannabis sativa L. has a long history as a medicinal plant and was fundamental in the discovery of the endocannabinoid system. The major psychoactive Cannabis constituent Delta(9)-tetrahydrocannabinol (Delta(9)-THC) potently activates the G-protein-coupled cannabinoid receptor CB(1) and also modulates the cannabinoid receptor CB(2). In the last few years, several other non-cannabinoid plant constituents have been reported to bind to and functionally interact with CB receptors. Moreover, certain plant natural products, from both Cannabis and other plants, also target other proteins of the endocannabinoid system, such as hydrolytic enzymes that control endocannabinoid levels. In this commentary we summarize and critically discuss recent findings.

New natural noncannabinoid ligands for cannabinoid type-2 (CB2) receptors

Since the discovery that Delta 9-tetrahydrocannabinol and related cannabinoids from Cannabis sativa L. act on specific physiological receptors in the human body and the subsequent elucidation of the mammalian endogenous cannabinoid system, no other natural product class has been reported to mimic the effects of cannabinoids. We recently found that N-alkyl amides from purple coneflower (Echinacea spp.) constitute a new class of cannabinomimetics, which specifically engage and activate the cannabinoid type-2 (CB2) receptors. Cannabinoid type-1 (CB1) and CB2 receptors belong to the family of G protein-coupled receptors and are the primary targets of the endogenous cannabinoids N-arachidonoyl ethanolamine and 2-arachidonoyl glyerol. CB2 receptors are believed to play an important role in distinct pathophysiological processes, including metabolic dysregulation, inflammation, pain, and bone loss. CB2 receptors have, therefore, become of interest as new targets in drug discovery. This review focuses on N-alkyl amide secondary metabolites from plants and underscores that this group of compounds may provide novel lead structures for the development of CB2-directed drugs.

Cannabinoid receptor ligands as potential anticancer agents--high hopes for new therapies?

OBJECTIVES: The endocannabinoid system is an endogenous lipid signalling network comprising arachidonic-acid-derived ligands, cannabinoid (CB) receptors, transporters and endocannabinoid degrading enzymes. The CB(1) receptor is predominantly expressed in neurons but is also co-expressed with the CB(2) receptor in peripheral tissues. In recent years, CB receptor ligands, including Delta(9)-tetrahydrocannabinol, have been proposed as potential anticancer agents. KEY FINDINGS: This review critically discusses the pharmacology of CB receptor activation as a novel therapeutic anticancer strategy in terms of ligand selectivity, tissue specificity and potency. Intriguingly, antitumour effects mediated by cannabinoids are not confined to inhibition of cancer cell proliferation; cannabinoids also reduce angiogenesis, cell migration and metastasis, inhibit carcinogenesis and attenuate inflammatory processes. In the last decade several new selective CB(1) and CB(2) receptor agents have been described, but most studies in the area of cancer research have used non-selective CB ligands. Moreover, many of these ligands exert prominent CB receptor-independent pharmacological effects, such as activation of the G-protein-coupled receptor GPR55, peroxisome proliferator-activated receptor gamma and the transient receptor potential vanilloid channels. SUMMARY: The role of the endocannabinoid system in tumourigenesis is still poorly understood and the molecular mechanisms of cannabinoid anticancer action need to be elucidated. The development of CB(2)-selective anticancer agents could be advantageous in light of the unwanted central effects exerted by CB(1) receptor ligands. Probably the most interesting question is whether cannabinoids could be useful in chemoprevention or in combination with established chemotherapeutic agents.

The preimplantation mouse embryo is a target for cannabinoid ligand-receptor signaling.

Using a reverse transcription-coupled PCR, we demonstrated that both brain and spleen type cannabinoid receptor (CB1-R and CB2-R, respectively) mRNAs are expressed in the preimplantation mouse embryo. The CB1-R mRNA expression was coincident with the activation of the embryonic genome late in the two-cell stage, whereas the CB2-R mRNA was present from the one-cell through the blastocyst stages. The major psychoactive component of marijuana (-)-delta-9-tetrahydrocannabinol [(-)-THC] inhibited forskolin-stimulated cAMP generation in the blastocyst, and this inhibition was prevented by pertussis toxin. However, the inactive cannabinoid cannabidiol (CBD) failed to influence this response. These results suggest that cannabinoid receptors in the embryo are coupled to inhibitory guanine nucleotide binding proteins. Further, the oviduct and uterus exhibited the enzymatic capacity to synthesize the putative endogenous cannabinoid ligand arachidonylethanolamide (anandamide). Synthetic and natural cannabinoid agonists [WIN 55,212-2, CP 55,940, (-)-THC, and anandamide], but not CBD or arachidonic acid, arrested the development of two-cell embryos primarily between the four-cell and eight-cell stages in vitro in a dose-dependent manner. Anandamide also interfered with the development of eight-cell embryos to blastocysts in culture. The autoradiographic studies readily detected binding of [3H]anandamide in embryos at all stages of development. Positive signals were present in one-cell embryos and all blastomeres of two-cell through four-cell embryos. However, most of the binding sites in eight-cell embryos and morulae were present in the outer cells. In the blastocyst, these signals were primarily localized in the mural trophectoderm with low levels of signals in the polar trophectoderm, while little or no signals were noted in inner cell mass cells.These results establish that the preimplantation mouse embryo is a target for cannabinoid ligands. Consequently, many of the adverse effects of cannabinoids observed during pregnancy could be mediated via these cannabinoid receptors. Although the physiological significance of the cannabinoid ligand-receptor signaling in normal preimplantation embryo development is not yet clear, the regulation of embryonic cAMP and/or Ca2+ levels via this signaling pathway may be important for normal embryonic development and/or implantation.

Cannabinoid ligand-receptor signaling in the mouse uterus.

Using RNA (Northern) blot hybridization and reverse transcription-PCR, we demonstrate that the brain-type cannabinoid receptor (CB1-R) mRNA, but not the spleen-type cannabinoid receptor (CB2-R) mRNA, is expressed in the mouse uterus and that this organ has the capacity to synthesize the putative endogenous cannabinoid ligand, anandamide (arachidonylethanolamide). The psychoactive cannabinoid component of marijuana--delta 9-tetrahydrocannabinol (THC)--or anandamide, but not the inactive and nonpsychoactive cannabidiol (CBD), inhibited forskolin-stimulated cyclic AMP formation in the mouse uterus, which was prevented by pertussis toxin pretreatment. These results suggest that uterine CB1-R is coupled to inhibitory guanine nucleotide-binding protein and is biologically active. Autoradiographic studies identified ligand binding sites ([3H]anandamide) in the uterine epithelium and stromal cells, suggesting that these cells are perhaps the targets for cannabinoid action. Scatchard analysis of the binding of [3H]WIN 55212-2, another cannabinoid receptor ligand, showed a single class of high-affinity binding sites in the endometrium with an apparent Kd of 2.4 nM and Bmax of 5.4 x 10(9) molecules per mg of protein. The gene encoding lactoferrin is an estrogen-responsive gene in the mouse uterus that was rapidly and transiently up-regulated by THC, but not by CBD, in ovariectomized mice in the absence of ovarian steroids. This effect, unlike that of 17 beta-estradiol (E2), was not influenced by a pure antiestrogen, ICI 182780, suggesting that the THC-induced uterine lactoferrin gene expression does not involve estrogen receptors. We propose that the uterus is a new target for cannabinoid ligand-receptor signaling.

Being stoned: A review of self-reported cannabis effects

Although there has been considerable research into the adverse effects of cannabis, less attention has been directed toward subjective effects that may be associated with ongoing cannabis use. Examination of self-reported cannabis effects is an important issue in understanding the widespread use of cannabis. While reviews have identified euphoria as a primary factor in maintaining cannabis use, relaxation is the effect reported most commonly in naturalistic studies of cannabis users, irrespective of the method used. Self-reported effects in 12 naturalistic and 18 laboratory studies were compared. Regardless of methodology there was considerable variation in the effects experienced. Variation has been reported in terms of opposite effects being experienced by different individuals, variation of effects by individuals within a single occasion and between occasions of use. Factors that might explain this variation are outlined. Limitations of the available literature and suggested directions for future research are discussed.

Is cannabis a gateway drug? Testing hypotheses about the relationship between cannabis use and the use of other illicit drugs

We outline and evaluate competing explanations of three relationships that have consistently been found between cannabis use and the use of other illicit drugs, namely, ( 1) that cannabis use typically precedes the use of other illicit drugs; and that ( 2) the earlier cannabis is used, and ( 3) the more regularly it is used, the more likely a young person is to use other illicit drugs. We consider three major competing explanations of these patterns: ( 1) that the relationship is due to the fact that there is a shared illicit market for cannabis and other drugs which makes it more likely that other illicit drugs will be used if cannabis is used; ( 2) that they are explained by the characteristics of those who use cannabis; and ( 3) that they reflect a causal relationship in which the pharmacological effects of cannabis on brain function increase the likelihood of using other illicit drugs. These explanations are evaluated in the light of evidence from longitudinal epidemiological studies, simulation studies, discordant twin studies and animal studies. The available evidence indicates that the association reflects in part but is not wholly explained by: ( 1) the selective recruitment to heavy cannabis use of persons with pre-existing traits ( that may be in part genetic) that predispose to the use of a variety of different drugs; ( 2) the affiliation of cannabis users with drug using peers in settings that provide more opportunities to use other illicit drugs at an earlier age; ( 3) supported by socialisation into an illicit drug subculture with favourable attitudes towards the use of other illicit drugs. Animal studies have raised the possibility that regular cannabis use may have pharmacological effects on brain function that increase the likelihood of using other drugs. We conclude with suggestions for the type of research studies that will enable a decision to be made about the relative contributions that social context, individual characteristics, and drug effects make to the relationship between cannabis use and the use of other drugs.

The development of Cannabidiol as a psychiatric therapeutic:a review of its antipsychotic efficacy and possible underlying pharmacodynamic mechanisms

Cannabidiol (CBD), a once-considered inert cannabis constituent, is one of two primary constituents of cannabis, alongside delta-9-tetrahydrocannabinol (?9-THC/THC). In the last 30 years, CBD has become implicated with a range of pharmaceutical mechanisms of great therapeutic interest and utility. This review details the literature speculating CBD’s attenuation of psychotic symptoms, particularly in light of a marked elevation in mean THC concentrations, and a concomitant decline in CBD concentrations in the prevalent U.K street market cannabis derivatives since c. 2000. CBD is purported to exhibit pharmacology akin to established atypical antipsychotics, whilst THC has been implicated with the precipitation of psychosis, and the induction of associated symptoms. The aim of the review was to clarify the conjecture surrounding CBD’s antipsychotic efficacy, before going on to detail prominent theories about its associated pharmacodynamics. Were CBD’s antipsychotic efficacy established, then there is potential for major latent anthropological repercussions to manifest, such as significant elevations in psychosis manifestations in the U.K. The review found a largely affirmative body of evidence asserting CBD’s antipsychotic efficacy. CBD exhibited capacity to attenuate natural and artificially induced psychoses in both animal and human cohorts, the latter of which included individuals considered resistant to conventional treatment. CBD also shows promising potential for use as an antipsychotic drug for Parkinson’s disease (PD) patients with psychosis, owing to its low rate of extra-pyramidal side-effect induction. A range of potential pharmacological mechanisms behind CBD’s neuroleptic pharmacology are outlined, with particular emphasis on its prevention of the hydrolysis and reuptake of the endogenous cannabinoid, anandamide. However, given the nebular aetiological basis for psychoses, explicit conclusions on how CBD attenuates psychotic symptoms remains to be determined.

Effect of (-)-∆9-tetrahydrocannabinoid on the hepatic redox state of mice

(-)-∆9-Tetrahydrocannabinol (∆9-THC), a psychoactive component of marijuana, has been reported to induce oxidative damage in vivo and in vitro. In this study, we administered ∆9-THC to healthy C57BL/6J mice aged 15 weeks in order to determine its effect on hepatic redox state. Mice were divided into 3 groups: ∆9-THC (N = 10), treated with 10 mg/kg body weight ∆9-THC daily; VCtrl (N = 10), treated with vehicle [1:1:18, cremophor EL® (polyoxyl 35 castor oil)/ethanol/saline]; Ctrl (N = 10), treated with saline. Animals were injected ip twice a day with 5 mg/kg body weight for 10 days. Lipid peroxidation, protein carbonylation and DNA oxidation were used as biomarkers of oxidative stress. The endogenous antioxidant defenses analyzed were glutathione (GSH) levels as well as enzyme activities of superoxide dismutase, catalase, glutathione S-transferase, glutathione reductase, and glutathione peroxidase (GPx) in liver homogenates. The levels of mRNA of the cannabinoid receptors CB1 and CB2 were also monitored. Treatment with ∆9-THC did not produce significant changes in oxidative stress markers or in mRNA levels of CB1 and CB2 receptors in the liver of mice, but attenuated the increase in the selenium-dependent GPx activity (Δ9-THC: 8%; VCtrl: 23% increase) and the GSH/oxidized GSH ratio (Δ9-THC: 61%; VCtrl: 96% increase), caused by treatment with the vehicle. Δ9-THC administration did not show any harmful effects on lipid peroxidation, protein carboxylation or DNA oxidation in the healthy liver of mice but attenuated unexpected effects produced by the vehicle containing ethanol/cremophor EL®.