Cannabidiol (CBD) but not tetrahydrocannabinol (THC) dysregulate in vitro decidualization of human endometrial stromal cells by disruption of estrogen signaling

Decidualization, which comprises proliferation and differentiation of endometrial stromal cells (ESCs), is essential for the establishment of a receptive endometrium and pregnancy to occur. A deregulation of decidualization has been associated with miscarriage, infertility and other pregnancy-related disorders. The role of estradiol (E₂) on decidualization has already been shown, since it regulates proliferation of ESCs and expression of progesterone receptor. In this study, we investigated the effects of phytocannabinoids, tetrahydrocannabinol (THC) and cannabidiol (CBD), in proliferation and differentiation of ESCs, as well as, in E₂ metabolism/signaling. We found that CBD, but not THC, inhibits ESCs differentiation. We also show that CBD prevents the increase on transcript levels of CYP19A1 gene and the elevation of E₂ levels that are observed in differentiating ESCs. Moreover, we found that CBD presents anti-aromatase activity. In overall, we highlight a novel effect of CBD on human endometrial differentiation, which may lead to infertility problems.

Chronic adolescent exposure to ∆9-tetrahydrocannabinol decreases NMDA current and extrasynaptic plasmalemmal density of NMDA GluN1 subunits in the prelimbic cortex of adult male mice

Adolescence is a vulnerable period of development when limbic connection of the prefrontal cortex (PFC) involved in emotional processing may be rendered dysfunctional by chronic exposure to delta-9-tetrahydrocannabinol (∆9-THC), the major psychoactive compound in marijuana. Cannabinoid-1 receptors (CB1Rs) largely mediate the central neural effects of ∆9-THC and endocannabinoids that regulate NMDA receptor-dependent synaptic plasticity of glutamatergic synapses in the prelimbic prefrontal cortex (PL-PFC). Thus, chronic occupancy of CB1Rs by ∆9-THC during adolescence may competitively decrease the functional expression and activity of NMDA receptors in the mature PL-PFC. We used a multidisciplinary approach to test this hypothesis in adult C57BL/6J male mice that received vehicle or ∆9-THC in escalating doses (2.5-10 mg/kg/ip) through adolescence (postnatal day 29-43). In comparison with vehicle, the mice receiving ∆9-THC showed a hyperpolarized resting membrane potential, decreased spontaneous firing rate, increased current-induced firing threshold, and decreased depolarizing response to NMDA in deep-layer PL-PFC neurons analyzed by current-clamp recordings. Electron microscopic immunolabeling in the PL-PFC of adult mice that had received Δ9-THC only during adolescence showed a significant (1) decrease in the extrasynaptic plasmalemmal density of obligatory GluN1-NMDA subunits in dendrites of all sizes and (2) a shift from cytoplasmic to plasmalemmal distribution of GluN1 in large dendrites receiving mainly inhibitory-type synapses from CB1R-labeled terminals. From these results and concomitant behavioral studies, we conclude that social dysfunctions resulting from excessive intake of ∆9-THC in the increasingly available marijuana products used by male teens may largely reflect circuit defects in PL-PFC networks communicating through endocannabinoid-regulated NMDA receptors.

Different effects of prenatal MAM vs. perinatal THC exposure on regional cerebral blood perfusion detected by Arterial Spin Labelling MRI in rats

Clinical studies consistently report structural impairments (i.e.: ventricular enlargement, decreased volume of anterior cingulate cortex or hippocampus) and functional abnormalities including changes in regional cerebral blood flow in individuals suffering from schizophrenia, which can be evaluated by magnetic resonance imaging (MRI) techniques. The aim of this study was to assess cerebral blood perfusion in several schizophrenia-related brain regions using Arterial Spin Labelling MRI (ASL MRI, 9.4 T Bruker BioSpec 94/30USR scanner) in rats. In this study, prenatal exposure to methylazoxymethanol acetate (MAM, 22 mg/kg) at gestational day (GD) 17 and the perinatal treatment with Δ-9-tetrahydrocannabinol (THC, 5 mg/kg) from GD15 to postnatal day 9 elicited behavioral deficits consistent with schizophrenia-like phenotype, which is in agreement with the neurodevelopmental hypothesis of schizophrenia. In MAM exposed rats a significant enlargement of lateral ventricles and perfusion changes (i.e.: increased blood perfusion in the circle of Willis and sensorimotor cortex and decreased perfusion in hippocampus) were detected. On the other hand, the THC perinatally exposed rats did not show differences in the cerebral blood perfusion in any region of interest. These results suggest that although both pre/perinatal insults showed some of the schizophrenia-like deficits, these are not strictly related to distinct hemodynamic features.

Effects of cannabis tetrahydrocannabinol on endocannabinoid homeostasis in human placenta

Cannabis use has become a hot topic in several countries due to the debate about its legalization for medical purposes. However, data are limited regarding adverse events, safety and potential impact on reproductive health. Cannabis consumption during pregnancy has been associated with gestational disorders such as preterm birth, intrauterine growth restriction, low birth weight and increased risk of miscarriage, though the underlying biochemical mechanisms are still unknown. Given that the endocannabinoid system (ECS) is involved in several reproductive processes, we tested the hypothesis that the negative outcomes may result from the impact on the ECS homeostasis caused by the main psychoactive compound of cannabis, Δ⁹-tetrahydrocannabinol (THC). We demonstrate that THC (10-40 µM) impairs placental endocannabinoid system by disrupting the endocannabinoid anandamide (AEA) levels and the expression of AEA synthetic and degrading enzymes N-arachidonoylphosphatidylethanolamine-specific phospholipase D (NAPE-PLD) and fatty acid amide hydrolase (FAAH), respectively. Although, no alterations in cannabinoid receptors CB1 and CB2 expression were observed. Thus, long-term local AEA levels are associated with a shift in the enzymatic profile to re-establish ECS homeostasis. In chronic cannabis users, high AEA levels in placenta may disturb the delicate balance of trophoblast cells turnover leading to alterations in normal placental development and foetal growth.

Astrocytic Mechanisms Involving Kynurenic Acid Control Δ9-Tetrahydrocannabinol-Induced Increases in Glutamate Release in Brain Reward-Processing Areas

The reinforcing effects of Δ⁹-tetrahydrocannabinol (THC) in rats and monkeys, and the reinforcement-related dopamine-releasing effects of THC in rats, can be attenuated by increasing endogenous levels of kynurenic acid (KYNA) through systemic administration of the kynurenine 3-monooxygenase inhibitor, Ro 61-8048. KYNA is a negative allosteric modulator of α7 nicotinic acetylcholine receptors (α7nAChRs) and is synthesized and released by astroglia, which express functional α7nAChRs and cannabinoid CB1 receptors (CB1Rs). Here, we tested whether these presumed KYNA autoreceptors (α7nAChRs) and CB1Rs regulate glutamate release. We used in vivo microdialysis and electrophysiology in rats, RNAscope in situ hybridization in brain slices, and primary culture of rat cortical astrocytes. Acute systemic administration of THC increased extracellular levels of glutamate in the nucleus accumbens shell (NAcS), ventral tegmental area (VTA), and medial prefrontal cortex (mPFC). THC also reduced extracellular levels of KYNA in the NAcS. These THC effects were prevented by administration of Ro 61-8048 or the CB1R antagonist, rimonabant. THC increased the firing activity of glutamatergic pyramidal neurons projecting from the mPFC to the NAcS or to the VTA in vivo. These effects were averted by pretreatment with Ro 61-8048. In vitro, THC elicited glutamate release from cortical astrocytes (on which we demonstrated co-localization of the CB1Rs and α7nAChR mRNAs), and this effect was prevented by KYNA and rimonabant. These results suggest a key role of astrocytes in interactions between the endocannabinoid system, kynurenine pathway, and glutamatergic neurotransmission, with ramifications for the pathophysiology and treatment of psychiatric and neurodegenerative diseases.

The psychoactive compound of Cannabis sativa, Δ(9)-tetrahydrocannabinol (THC) inhibits the human trophoblast cell turnover

The noxious effects of cannabis consumption for fertility and pregnancy outcome are recognized for years. Its consumption during gestation is associated with alterations in foetal growth, low birth weight and preterm labor. The main psychoactive molecule of cannabis, Δ(9)-tetrahydrocannabinol (THC) impairs the production of reproductive hormones and is also able to cross the placenta barrier. However, its effect on the main placental cells, the trophoblasts, are unknown. Actually, the role of THC in cell survival/death of primary human cytotrophoblasts (CTs) and syncytiotrophoblasts (STs) and in the syncytialization process remains to be explored. Here, we show that THC has a dual effect, enhancing MTT metabolism at low concentrations, whereas higher doses decreased cell viability, on both trophoblast phenotypes, though the effects on STs were more evident. THC also diminished the generation of oxidative and nitrative stress and the oxidized form of glutathione, whereas the reduced form of this tripeptide was increased, suggesting that THC prevents ST cell death due to an antioxidant effect. Moreover, this compound enhanced the mitochondrial function of STs, as observed by the increased MTT metabolism and intracellular ATP levels. These effects were independent of cannabinoid receptors activation. Besides, THC impaired CT differentiation into STs, since it decreased the expression of biochemical and morphological biomarkers of syncytialization, through a cannabinoid receptor-dependent mechanism. Together, these results suggest that THC interferes with trophoblast turnover, preventing trophoblast cell death and differentiation, and contribute to disclose the cellular mechanisms that lead to pregnancy complications in women that consume cannabis-derived drugs during gestation.

Exposure to Δ9-Tetrahydrocannabinol Impairs the Differentiation of Human Monocyte-derived Dendritic Cells and their Capacity for T cell Activation

The capacity for human monocytes to differentiate into antigen-presenting dendritic cells (DC) can be influenced by a number of immune modulating signals. Monocytes express intracellular cannabinoid type 1 (CB1) and 2 (CB2) receptors and we demonstrate that exposure to Δ9-tetrahydrocannabinol (THC) inhibits the forskolin-induced generation of cyclic adenosine monophosphate in a CB2-specific manner. In order to examine the potential impact of cannabinoids on the generation of monocyte-derived DC, monocytes were cultured in vitro with differentiation medium alone [containing granulocyte/macrophage-colony stimulating factor (GM-CSF) and Interleukin-4 (IL-4)] or in combination with THC. The presence of THC (0.25-1.0 μg/ml) altered key features of DC differentiation, producing a concentration-dependent decrease in surface expression of CD11c, HLA-DR and costimulatory molecules (CD40 and CD86), less effective antigen uptake, and signs of functional skewing with decreased production of IL-12 but normal levels of IL-10. When examined in a mixed leukocyte reaction, DC that had been generated in the presence of THC were poor T cell activators as evidenced by their inability to generate effector/memory T cells or to stimulate robust IFN-γ responses. Some of these effects were partially restored by exposure to exogenous IL-7 and bacterial superantigen (S. aureus Cowans strain). These studies demonstrate that human monocytes express functional cannabinoid receptors and suggest that exposure to THC can alter their differentiation into functional antigen presenting cells; an effect that may be counter-balanced by the presence of other immunoregulatory factors. The impact of cannabinoids on adaptive immune responses in individuals with frequent drug exposure remains to be determined.

Effect of Delta-9-tetrahydrocannabinol on mouse resistance to systemic Candida albicans infection

Delta-9-tetrahydrocannabinol (Δ⁹-THC), the psychoactive component of marijuana, is known to suppress the immune responses to bacterial, viral and protozoan infections, but its effects on fungal infections have not been studied. Therefore, we investigated the effects of chronic Δ⁹-THC treatment on mouse resistance to systemic Candida albicans (C. albicans) infection. To determine the outcome of chronic Δ⁹-THC treatment on primary, acute systemic candidiasis, c57BL/6 mice were given vehicle or Δ⁹-THC (16 mg/kg) in vehicle on days 1–4, 8–11 and 15–18. On day 19, mice were infected with 5×10⁵C. albicans. We also determined the effect of chronic Δ⁹-THC (4–64 mg/kg) treatment on mice infected with a non-lethal dose of 7.5×10⁴C. albicans on day 2, followed by a higher challenge with 5×10⁵C. albicans on day 19. Mouse resistance to the infection was assessed by survival and tissue fungal load. Serum cytokine levels were determine to evaluate the immune responses. In the acute infection, chronic Δ⁹-THC treatment had no effect on mouse survival or tissue fungal load when compared to vehicle treated mice. However, Δ⁹-THC significantly suppressed IL-12p70 and IL-12p40 as well as marginally suppressed IL-17 versus vehicle treated mice. In comparison, when mice were given a secondary yeast infection, Δ⁹-THC significantly decreased survival, increased tissue fungal burden and suppressed serum IFN-γ and IL-12p40 levels compared to vehicle treated mice. The data showed that chronic Δ⁹-THC treatment decreased the efficacy of the memory immune response to candida infection, which correlated with a decrease in IFN-γ that was only observed after the secondary candida challenge.

Alterations of prefrontal cortex GABAergic transmission in the complex psychotic-like phenotype induced by adolescent delta-9-tetrahydrocannabinol exposure in rats

Although several findings indicate an association between adolescent cannabis abuse and the risk to develop schizophrenia later in life, the evidence for a causal relationship is still inconclusive. In the present study, we investigated the emergence of psychotic-like behavior in adult female rats chronically exposed to delta-9-tetrahydrocannabinol (THC) during adolescence. To this aim, female Sprague-Dawley rats were treated with THC during adolescence (PND 35-45) and, in adulthood (PND 75), a series of behavioral tests and biochemical assays were performed in order to investigate the long-term effects of adolescent THC exposure. Adolescent THC pretreatment leads to long-term behavioral alterations, characterized by recognition memory deficits, social withdrawal, altered emotional reactivity and sensitization to the locomotor activating effects of acute PCP. Moreover, since cortical disinhibition seems to be a key feature of many different animal models of schizophrenia and GABAergic hypofunction in the prefrontal cortex (PFC) has been observed in postmortem brains from schizophrenic patients, we then investigated the long-lasting consequences of adolescent THC exposure on GABAergic transmission in the adult rat PFC. Biochemical analyses revealed that adolescent THC exposure results in reduced GAD67 and basal GABA levels within the adult PFC. GAD67 expression is reduced both in parvalbumin (PV)- and cholecystokinin (CCK)-containing interneurons; this alteration may be related to the altered emotional reactivity triggered by adolescent THC, as silencing PFC GAD67 expression through a siRNA-mediated approach is sufficient to impact rats' behavior in the forced swim test. Finally, the cellular underpinnings of the observed sensitized response to acute PCP in adult THC-treated rats could be ascribed to the increased cFos immunoreactivity and glutamate levels in the PFC and dorsal striatum. The present findings support the hypothesis that adolescent THC exposure may represent a risk factor for the development of a complex psychotic-like behavior in adulthood.

Adolescent cannabinoid exposure permanently suppresses cortical oscillations in adult mice

Regular marijuana use during adolescence, but not adulthood, may permanently impair cognition and increase the risk for psychiatric diseases, such as schizophrenia. Cortical oscillations are integral for cognitive processes and are abnormal in patients with schizophrenia. We test the hypothesis that adolescence is a sensitive period because of the active development of cortical oscillations and neuromodulatory systems that underlie them. The endocannabinoid system upon which marijuana acts is one such system. Here we test the prediction that adolescent cannabinoid exposure alters cortical oscillations in adults. Using in vitro local field potential, in vivo electrocorticogram recordings and cognitive behavioral testing in adult mice, we demonstrate that chronic adolescent, but not adult, cannabinoid exposure suppresses pharmacologically evoked cortical oscillations and impairs working memory performance in adults. The later-maturing prefrontal cortex is more sensitive to adolescent exposure than the earlier-maturing, primary somatosensory cortex. These data establish a link between chronic adolescent cannabinoid exposure and alterations in adult cortical network activity that underlie cognitive processes.

Investigation of the transformation of 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol during water chlorination by liquid chromatography-quadrupole-time-of-flight-mass spectrometry

The stability of the main metabolite of cannabis, (±)-11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THCCOOH), during water chlorination has been investigated. THCCOOH was degraded in few seconds following a pseudo-first order kinetics. Sample pH turned out to be a significant factor, decreasing THCCOOH half-life with an increase in its values. Seven by-products could be positively identified from accurate mass measurements: three compounds resulted from electrophilic substitutions of hydrogen per chlorine (or bromine) in the aromatic ring, whereas the formation of the remaining four involved additional reactions in the C-C double bond (hydration and halogenation). The software predicted toxicity of these products towards Daphnia magna indicates that they are expected to have toxicity values similar or higher than its precursor compound. Experiments conducted with diluted urine showed that THCCOOH was stable in this matrix, probably due to a rapid and complete reaction between chlorine and other organic constituents already present in the samples. In real surface waters, the extent of the reaction was also affected by the organic matter content, and so THCCOOH was rapidly degraded in samples scarcely affected by human activities, being more stable in waters with a higher level of pollution.

[Does cannabis use lead to schizophrenia?]

There is a high comorbidity between cannabis use and schizophrenia. Several factors contribute to this comorbidity: secondary development of addiction, cannabis-related induction of psychosis and shared neurobiological alterations. Meanwhile, there is evidence that cannabis use is associated with an increased risk of schizophrenia. Prospective epidemiological studies have shown that a frequent cannabis use doubles the risk for schizophrenia. Interestingly, schizophrenic patients with comorbid cannabis use often show significantly better performances in neuropsychological tests than patients without cannabis use. This is nevertheless not due to a positive effect of cannabis, but a sign of cannabis-related psychosis induction in subjects with a higher level of function and less cognitive impairment. Whether cannabis use leads to schizophrenia is determined by the individual vulnerability.

Long-term behavioral and pharmacodynamic effects of delta-9-tetrahydrocannabinol in female rats depend on ovarian hormone status

Abuse of Δ⁹-THC by females during adolescence may produce long-term deficits in complex behavioral processes such as learning, and these deficits may be affected by the presence of ovarian hormones. To assess this possibility, 40 injections of saline or 5.6 mg/kg of Δ⁹-THC were administered i.p. daily during adolescence to gonadally intact or ovariectomized (OVX) female rats, yielding four treatment groups (intact/saline, intact/THC, OVX/saline, and OVX/ THC). Δ⁹-THC (0.56-10 mg/kg) was then re-administered to each of the four groups during adulthood to examine their sensitivity to its disruptive effects. The behavioral task required adult subjects to both learn (acquisition component) different response sequences and repeat a known response sequence (performance component) daily. During baseline (no injection) and control (saline injection) sessions, OVX subjects had significantly higher response rates and lower percentages of error in both behavioral components than the intact groups irrespective of saline or Δ⁹-THC administration during adolescence; the intact group that received Δ⁹-THC had the lowest response rates in each component. Upon re-administration of Δ⁹-THC, the groups that received adolescent ovariectomy alone, adolescent Δ⁹-THC administration alone, or both treatments were found to be less sensitive to the rate-decreasing effects, and more sensitive to the error-increasing effects of Δ⁹-THC than the control group (i.e. intact subjects that received saline during adolescence). Neurochemical analyses of the brains from each adolescent-treated group indicated that there were also persistent effects on cannabinoid type-1 (CB-1) receptor levels in the hippocampus and striatum that depended on the brain region and the presence of ovarian hormones. In addition, autoradiographic analyses of the brains from adolescent-treated, but behaviorally naïve, subjects indicated that ovariectomy and Δ⁹-THC administration produced effects on receptor coupling in some of the same brain regions. In summary, chronic administration of Δ⁹-THC during adolescence in female rats produced long-term effects on operant learning and performance tasks and on the cannabinoid system that were mediated by the presence of ovarian hormones, and that altered their sensitivity to Δ⁹-THC as adults.

Evidence that familial liability for psychosis is expressed as differential sensitivity to cannabis: an analysis of patient-sibling and sibling-control pairs

CONTEXT

Individual differences in cannabis sensitivity may be associated with genetic risk for psychotic disorder.

OBJECTIVES

To demonstrate and replicate, using 2 conceptually different genetic epidemiological designs, that (familial) liability to psychosis is associated with sensitivity to cannabis.

DESIGN, SETTING, AND PARTICIPANTS

Sibling-control and cross-sibling comparisons using samples of patients with a psychotic disorder (n = 1120), their siblings (n = 1057), and community controls (n = 590) in the Netherlands and Flanders.

MAIN OUTCOME MEASURES

Positive and negative schizotypy using the Structured Interview for Schizotypy-Revised (for siblings and controls) and self-reported positive and negative psychotic experiences using the Community Assessment of Psychic Experiences (for siblings and patients). Cannabis use was assessed as current use (by urinalysis) and lifetime frequency of use (by Composite International Diagnostic Interview).

RESULTS

In the sibling-control comparison, siblings displayed more than 15 times greater sensitivity to positive schizotypy associated with particularly current cannabis use by urinalysis (adjusted B = 0.197, P < .001) than controls (adjusted B = 0.013, P = .86) (P interaction = .04) and a similar difference in sensitivity to its effect on negative schizotypy (siblings: adjusted B = 0.120, P < .001; controls: B = -0.008, P = .87; P interaction = .03). Similarly, siblings exposed to cannabis resembled their patient relative nearly 10 times more closely in the positive psychotic dimension of the Community Assessment of Psychic Experiences (adjusted B = 0.278, P < .001) compared with nonexposed siblings (adjusted B = 0.025, P = .12) (P interaction < .001). No significant effect was apparent for the Community Assessment of Psychic Experiences negative domain, although the association was directionally similar (2 times more resemblance; P interaction = .17). Cross-sibling, cross-trait analyses suggested that the mechanism underlying these findings was moderation (familial risk increasing sensitivity to cannabis) rather than mediation (familial risk increasing use of cannabis).

CONCLUSIONS

Genetic risk for psychotic disorder may be expressed in part as sensitivity to the psychotomimetic effect of cannabis. Cannabis use may synergistically combine with preexisting psychosis liability to cause positive and negative symptoms of psychosis.

Cannabis and psychiatric disorders

There are connection between use of cannabis and many psychiatric disturbances in adolescents, especially "cannabis psychosis", depression, panic attacks and suicide. Negative effects could occur either as a result of a specific pharmacological effect of cannabis, or as the result of stressful experiences during the intoxication of cannabis in young people. Potentially is very dangerous high frequency suicidal ideation among cannabis users.

Cognitive effects of psychotomimetic drugs in rats discriminating number cues

RATIONALE

Deficits in memory and attention are broadly acknowledged during psychosis; however, experiments on modeled psychosis often test working memory without systematic manipulation of attentional demands.

OBJECTIVES

The major research goal was discovering which neurobehavioral processes, attention, or memory contributed more to drug-provoked performance deficits.

MATERIALS AND METHODS

Rats were trained to perform operant ratio discrimination (RD) tasks wherein the number of presses at a rear-wall lever was discriminated using one of two front-wall levers. Effects from four psychotomimetic drugs, the serotonin agonist 2,5-dimethoxy-4-iodoamphetamine, the noncompetitive NMDA-glutamate receptor antagonist phencyclidine (PCP), and two CB1-selective cannabinoid agonists, WIN 55,512-2 and AM 411, were assessed using a signal detection analytical overlay to dissociate cognitive from noncognitive motor and motivational disruptions. Further methods allowed dissociation of attention compromises from mnemonic deficits.

RESULTS

For each test compound, at least one dose elicited decreased RD accuracy without affecting response rates, and task difficulty was shown to be a crucial dictator of accuracy effect specificities. Effects from both PCP and WIN 55,512-2 biased animals to select the response lever conditioned for denser reinforcement. The same two drugs rendered peculiar response patterns in distracter light session components, considering light blinks were included to divert subjects' attention away from task-relevant information. The response patterns determined during distracter components of PCP/WIN testing sessions, counterintuitively, suggest performance enhancement.

CONCLUSION

Comprehensive viewing of RD performance patterns after drug administration indicates that sustained attention and transient information management are significantly impaired during the drug-induced psychosis state, while selective attention is less affected.

Puberty as a highly vulnerable developmental period for the consequences of cannabis exposure

During puberty, neuronal maturation of the brain, which began during perinatal development, is completed such that the behavioral potential of the adult organism can be fully achieved. These maturational events and processes of reorganization are needed for the occurrence of adult behavioral performance but simultaneously render the organism highly susceptible to perturbations, such as exposure to psychoactive drugs, during this critical developmental time span. Considering the variety of maturational processes occurring in the endocannabinoid system during this critical period, it is not surprising that the still-developing brain might by highly susceptible to cannabis exposure. Emerging evidence from human studies and animal research demonstrates that an early onset of cannabis consumption might have lasting consequences on cognition, might increase the risk for neuropsychiatric disorders, promote further illegal drug intake and increase the likelihood of cannabis dependence. These findings suggest that young people represent a highly vulnerable cannabis consumer group and that they run a higher risk than adult consumers of suffering from adverse consequences from cannabinoid exposure. The aim of the present review is to provide an overview over the possible deleterious residual cannabinoid effects during critical periods of postnatal maturation and to offer a more precise delineation of the vulnerable time window for cannabinoid exposure.

Cannabis and psychiatric disorders: it is not only addiction

Since the discovery of the endocannabinoid system, a growing body of psychiatric research has emerged focusing on the role of this system in major psychiatric disorders like schizophrenia (SCZ), bipolar disorder (BD), major depression and anxiety disorder. Continuing in the line of earlier epidemiological studies, recent replication studies indicate that frequent cannabis use doubles the risk for psychotic symptoms and SCZ. Further points of clinical research interest are alterations of endocannabinoids and their relation to symptoms as well as postmortem analyses of cannabinoid CB(1) receptor densities in SCZ. A possible neurobiological mechanism for the deleterious influence of cannabis use in SCZ has been suggested, involving the disruption of endogenous cannabinoid signaling and functioning. Even though the number of studies is still limited for affective and anxiety disorders, previous results suggest these diseases to be exciting objectives of cannabinoid-associated research. Therefore, it became apparent that cannabis use is not only frequent in patients suffering from BD, but that it also induces manic symptoms in this group. In addition, prior antipsychotic treatment decreased the numerical density of CB(1) immunoreactive glial cells in bipolar patients. Although the data on the influence of cannabis use on the development of major depression is controversial, cannabinoid compounds could display a new class of medication, as suggested by the antidepressive effects of the fatty acid amino hydrolase inhibitor URB597 in animal models. With numerous open questions and controversial results, further research is required to specify and extend the findings in this area, which provides a promising target for novel pharmacotherapeutic interventions.

Perinatal delta-9-tetrahydrocannabinol exposure disrupts social and open field behavior in adult male rats

Marijuana is the most frequently used illegal drug among women of reproductive age, but little is known about the consequences of using marijuana during pregnancy. Delta-9-tetrahydrocannabinol (Delta9-THC), one of the active chemicals in marijuana, has been shown to cross the placental barrier easily. In this study, pregnant Long Evans rats were assigned to one of three treatment groups (Delta9-THC-exposed, vehicle control, and non-treated control) on day 1 of gestation. Drug exposure consisted of 2 mg/kg of natural Delta9-THC, administered twice daily by subcutaneous (s.c.) injection, from gestational day 1 through 22. Pups continued to receive drug exposure via s.c. injection from postnatal day 2 through 10. Male rats from each group were tested starting on postnatal day 90 in a battery of tests which included open field activity, active social interaction, and the forced swim test. There were no significant differences in weight gained by dams or weight of offspring when compared to controls. Delta9-THC-exposed rats showed decreased time in the inner part of the open field and an increase in investigation time in the test of social interaction compared to both control groups. There were no differences among groups in the forced swim test. Perinatal Delta9-THC exposure may result in increased susceptibility to anxious behavior and alter social functioning in adult offspring.