Regular use of marijuana during adolescence enhances the risk of long‐lasting neurobiological changes in adulthood. The present study was aimed at assessing the effect of long‐term administration of ...the synthetic cannabinoid WIN55212.2 during adolescence in young adult mice. Adolescent mice aged 5 weeks were subjected daily to the pharmacological action of WIN55212.2 for 3 weeks and were then left undisturbed in their home cage for a 5‐week period and finally evaluated by behavioral testing. Mice that received the drug during adolescence showed memory impairment in the Morris water maze, as well as a dose‐dependent memory impairment in fear conditioning. In addition, the administration of 3 mg/kg WIN55212.2 in adolescence increased adult hippocampal AEA levels and promoted DNA hypermethylation at the intragenic region of the intracellular signaling modulator Rgs7, which was accompanied by a lower rate of mRNA transcription of this gene, suggesting a potential causal relation. Although the concrete mechanisms underlying the behavioral observations remain to be elucidated, we demonstrate that long‐term administration of 3 mg/kg of WIN during adolescence leads to increased endocannabinoid levels and altered Rgs7 expression in adulthood and establish a potential link to epigenetic changes.
Adolescent mice were subjected daily to WIN55212.2, then left undisturbed, and finally evaluated by behavioral testing at adulthood. Mice that received the drug during adolescence showed memory impairment, higher endocannabinoid levels and altered Rgs7 expression in adulthood, establishing a potential link to epigenetic changes.
•Repeated stress increased levels of Drd2 in the PFC.•Stressed mice displayed lower levels of Nrg1 in both PFC and CB.•The pharmacological manipulation of CB1 interfered with striatal levels of ...Drd2.•The drugs WIN55212.2 or Rimonabant under stress led to deficits in CNS myelination.•Rimonabant altered expression of dopamine receptors.
Repeated exposure to life stressors can overwhelm the body’s capacity to restore homeostasis and result in severe negative consequences. Cannabinoid CB1 receptors are highly expressed in the Central Nervous System (CNS) and regulate both glucocorticoid signalling and neurotransmitter release. In rodents, WIN55212.2 is a full agonist at the cannabinoid receptor type-1, while Rimonabant is a potent and selective cannabinoid inverse agonist at this receptor. This study aims to investigate the effect of long-term psychosocial stress following acute challenge with cannabinoid drugs on gene expression in distinct brain regions; this is done by employing digital multiplexed gene expression analysis.
We found that repeated stress increased cortical mRNA levels of dopamine receptor D2, while the expression of neuregulin-1 decreased in both the prefrontal cortex and cerebellum. Further, we found that the acute injection of the agonist WIN55212.2 reduced striatal levels of dopamine receptor D2, while the use of inverse agonist Rimonabant acted in the opposite direction. The analysis of the interaction between the drugs and repeated stress revealed that defeat mice treated with WIN55212.2 showed lower expression of a set of myelin-related genes, as did the expression of SRY-box 10 and dopamine receptors-D1 and -D2 in the prefrontal cortex when compared to vehicle. In addition, in the hippocampus of stressed mice treated with WIN55212.2, we found an elevated expression of oligodendrocyte transcription factor-1, -2 and zinc finger protein 488 when compared to vehicle. In comparison to vehicle, an increase in 2′,3′-Cyclic nucleotide 3′-phosphodiesterase and oligodendrocyte transcription factor-1 occurred in the cerebellum of stressed animals treated with the agonist. Moreover, treatment with Rimonabant under the influence of stress induced an overexpression of a set of myelin-related genes in the prefrontal cortex when compared to WIN-treated animals.
In conclusion, repeated stress interfered with the dopaminergic system in the prefrontal cortex. We demonstrated that the expression of dopamine receptor D2 in the striatum was mediated by the CB1 receptor. Stressed mice exposed to either WIN55212.2 or Rimonabant displayed pronounced deficits in CNS myelination. In addition, the pharmacological blockage of CB1 receptor in stressed mice deregulated the expression of dopamine receptors and might lead to dysfunctions in dopamine metabolism.
Dysfunctions in the endocannabinoid system have been associated with experimental animal models and multiple sclerosis patients. Interestingly, the endocannabinoid system has been reported to confer ...neuroprotection against demyelination. The present study aims to assess the effects of the cannabinoid agonist WIN-55,212-2 in cuprizone fed animals on myelin repair capacity. Animals exposed to cuprizone were simultaneously treated withWIN-55,212-2, behaviorally tested and finally the corpus callosum was exhaustively studied by Western blotting, qRT-PCR and a myelin staining procedure. We report that the long-term administration of WIN-55,212-2 reduced the global amount of CB
protein. Histological analysis revealed clear demyelination after being fed cuprizone for three weeks. However, cuprizone-fed mice subjected to 0.5 mg/Kg of WIN-55,212-2 displayed no differences when compared to controls during demyelination, although there was a robust increase in the myelinated axons during the remyelination phase. These animals displayed better performance on contextual fear conditioning which was in turn non-attributable to an antinociceptive effect. In contrast, a 1 mg/Kg dosage caused a remarkable demyelination accompanied by limited potential for myelin repair. Upon drug administration while mice ongoing demyeliniation, the expression of Aif1 (microglia) and Gfap (astrocytes) followed a dose-dependent manner whereas the expression of both markers was apparently attenuated during remyelination. Treatment with vehicle or 0.5 mg/Kg of the drug during demyelination increased the expression of Pdgfra (oligodendrocyte precursor cells) but this did not occur when 1 mg/Kg was administered. In conclusion, the drug at 0.5 mg/Kg did not alter myelin architecture while 1 mg/Kg had a deleterious effect in this model.
•Demyelinated animals showed less grooming activity and worse motor coordination.•At 6 weeks, CPZ-fed animals showed impairments in sensorimotor and exploratory behaviour.•Animals undergoing ...remyelination displayed less rearings, worse motor coordination, gait abnormalities and anxiety.•At 10 weeks, CPZ-fed mice displayed worse limb coordination and an anxiogenic response.•Recovered mice showed dysfunctions in sensorimotor, neuromuscular, motor coordination and coping with a stress event.
Destruction of the myelin sheath in the central nervous system (CNS) is prominent in many clinico-pathologic conditions. Among animal models that reproduce the pathological features of de- and remyelination processes, the mouse model of cuprizone administration is widely used. Both hyperactivity and motor impairment have been reported upon cuprizone exposure. The aim of the present study was to assess behaviour in mice after CPZ withdrawal.To summarize, animals showed hypo-activity and deficits in motor coordination when they were subjected to acute demyelinating insult while minor exploratory activity, impairment in motor coordination and lower anxiety levels emerged when remyelination was reached following cuprizone withdrawal. A recovery period of 6 weeks after removal of CPZ was not accompanied by a similar return of normal activity indicating long lasting behavioural effects caused by this neurotoxicant. Specifically, the recovery group showed impairments in neurological functions involved in sensorimotor, neuromuscular, motor coordination and the capacity to cope with a stress-inducing event.
Background and purpose
Chitinase 3‐like 1 (CHI3L1) and neurofilament light chain (NF‐L) are promising biomarkers of disability in multiple sclerosis (MS). However, their role in cognitive dysfunction ...remains elusive. Here, we aimed to correlate cerebrospinal fluid (CSF) levels of CHI3L1 and NF‐L with cognitive status in MS.
Methods
Fifty one recently diagnosed patients were cognitively evaluated and CSF was collected. Levels of CHI3L1 and NF‐L were determined by ELISA. Spearman's partial correlation coefficient was performed.
Results
After adjusting cognitive scores by age, anxiety and EDSS, association was detected between CHI3L1 levels and Trail Making Test A (rs = 0.348; p = 0.016) and between NF‐L levels and Word List Generation (rs = −0.324; p = 0.025).
Conclusion
High levels of CSF CHI3L1 and NF‐L are associated with cognitive impairment in the early phases of MS.
•Motor coordination and motor learning are compromised in social defeat mice.•After three weeks of social stress, the cerebellum of stressed mice compared to control non-stressed mice showed higher ...2-AG concentration and lower CB1 mRNA and protein expression.•Next Generation Sequencing revealed an increase in calreticulin expression after 3 weeks of chronic psychosocial stress.
Prolonged and sustained stimulation of the hypothalamo–pituitary–adrenal axis have adverse effects on numerous brain regions, including the cerebellum. Motor coordination and motor learning are essential for animal and require the regulation of cerebellar neurons. The G-protein-coupled cannabinoid CB1 receptor coordinates synaptic transmission throughout the CNS and is of highest abundance in the cerebellum. Accordingly, the aim of this study was to investigate the long-lasting effects of chronic psychosocial stress on motor coordination and motor learning, CB1 receptor expression, endogenous cannabinoid ligands and gene expression in the cerebellum.
After chronic psychosocial stress, motor coordination and motor learning were impaired as indicated the righting reflex and the rota-rod. The amount of the endocannabinoid 2-AG increased while CB1 mRNA and protein expression were downregulated after chronic stress. Transcriptome analysis revealed 319 genes differentially expressed by chronic psychosocial stress in the cerebellum; mainly involved in synaptic transmission, transmission of nerve impulse, and cell-cell signaling. Calreticulin was validated as a stress candidate gene.
The present study provides evidence that chronic stress activates calreticulin and might be one of the pathological mechanisms underlying the motor coordination and motor learning dysfunctions seen in social defeat mice.
Introduction Aim of study to investigate the consequences of chronic psychosocial stress on behavior, endocannabinoids and CBR expression in prefrontal cortex (PFC) and striatum of mice. Materials ...And Methods Psychosocial stress was induced in adult C57Bl/6 mice by resident-intruder paradigm (Brzózka et al. 2011). After 3 weeks daily exposure to psychosocial stress for 1 hour, animals were studied during the rodent active phase (night) by behavioral tests such as Functional Observational Battery (FOB), Rota-Rod (R-R), Open Field (OF), Prepulse Inhibition test (PPI). After behavioral testing, mice were sacrificed. 4 mice brains (prefrontal cortex, dorsal striatum) were studied by LC-MS to estimate the concentration of anandamide (AEA), 2- arachidonoylglycerol (2-AG), N-oleoylethanolamine (OEA), palmitoylethanolamide (PEA) (coll. di Marzo). In Situ Hybridization (ISH)and Immunohistochemistry (IHCH) against CB1 receptor were performed on free floating brain coronal sections fixed by 4% paraformaldehyde (coll del Río). Results 1. After psychosocial stress, mice displayed lower body weight (p<0.01), higher scratching and miccions activity compared to controls (p<0.05), decreased number of falls (p<0.01) and increased latency (p<0.05) in Rotarod. No effects in PPI were found. 2. In the same mice psychosocial stress reduced AEA levels in dorsal striatum and PFC (p<0.05). Endocannabinoids significantly showed an inverse relationship in PFC compared to striatum in control mice (AEA, p<0.001; 2-AG, p<0.001; OEA, p<0.001) and in psychosocially stressed mice (PEA, p<0.001; OEA, p<0.001). 3. Psychosocial stress increased the protein CBR1 expression in striatum (p<0.05) but not in prefrontal cortex. Conclusion Chronic psychosocial stress significantly changes behavior, endocannabinoids, CB receptor function and the striatal-cortical connectivity. These changes may contribute to vulnerability for psychosis and addiction.
Aim of the study: to examine the role of endocannabinoids and CB1 receptors in psychosocial (PS) stress in mice. PS stress was induced in C57Bl/6 mice by resident-intruder paradigm (Brzózka et al. ...2010). After 3 weeks PS stress anandamide (AEA), 2-arachidonoylglycerol (2-AG), N-oleoylethanolamine (OEA) and palmitoylethanolamide (PEA) were estimated in hippocampus, prefrontal cortex, striatum and cerebellum. Identically stressed and control mice (N = 15) were injected with WIN55212.2 (3 mg/kg) ± Rimonabant (3 mg/kg). Functional Observational Battery (FOB) (Golub et al., 2004), Open Field (OF), Prepulse Inhibition test (PPI) were studied. All behavioral recordings were done at night. Stressed mice showed significantly lowered AEA and OEA in Hippocampus, significant increase of 2-AG in Cortex, decrease of OEA in Striatum and increase of 2-AG in Cerebellum. Stressed mice displayed significantly lowered body weight gain, higher scratching activity, decrease of righting reflex time in FOB, higher distance travelled, time moving and hyperactivity in OF. In stressed mice WIN55212.2 significantly lowered rearings, increased righting reflex time, reduced distance travelled, time moving and hyperactivity in OF. Rimonabant did not significantly antagonize the effect of WIN55212.2 in stressed mice, but in controls. In controls WIN55212.2 significantly increased the number of scratches, reduced distance travelled, time moving and climbing and increased the startle response amplitude in PPI. The latter effect was significantly antagonized by Rimonabant. To sum up significant stress effects could be recorded in behavior, but less in PPI. PPI seems to be dependent on CB1-receptor processes but in case of stress endocannabinoids-activities may contribute.
Summary
Introduction
Vulnerability to psychiatric manifestations is achieved by the influence of genetic and environment including stress and cannabis consumption. Here, we used a psychosocial stress ...model based on resident‐intruder confrontations to study the brain corticostriatal‐function, since deregulation of corticostriatal circuitries has been reported in many psychiatric disorders. CB1 receptors are widely expressed in the central nervous system and particularly, in both cortex and striatum brain structures.
Aims and methods
The investigation presented here is addressed to assess the impact of repeated stress following acute cannabinoid exposure on behavior and corticostriatal brain physiology by assessing mice behavior, the concentration of endocannabinoid and endocannabinoid‐like molecules and changes in the transcriptome.
Results
Stressed animals urinated frequently; showed exacerbated scratching activity, lower striatal N‐arachidonylethanolamine (AEA) levels and higher cortical expression of cholinergic receptor nicotinic alpha 6. The cannabinoid agonist WIN55212.2 diminished locomotor activity while the inverse agonist increased the distance travelled in the center of the open field. Upon CB1 activation, N‐oleoylethanolamide and N‐palmitoylethanolamide, two AEA congeners that do not interact directly with cannabinoid receptors, were enhanced in the striatum. The co‐administration with both cannabinoids induced an up‐regulation of striatal FK506 binding protein 5. The inverse agonist in controls reversed the effects of WIN55212.2 on motor activity. When Rimonabant was injected under stress, the cortical levels of 2‐arachidonoylglycerol were maximum. The agonist and the antagonist influenced the cortical expression of cholinergic receptor nicotinic alpha 6 and serotonin transporter neurotransmitter type 4 in opposite directions, while their co‐administration tended to produce a null effect under stress.
Conclusions
The endocannabinoid system had a direct effect on serotoninergic neurotransmission and glucocorticoid signaling. Cholinergic receptor nicotinic alpha‐6 was shown to be deregulated in response to stress and following synthetic cannabinoid drugs thus could confer vulnerability to cannabis addiction and psychosis. Targeting the receptors of endocannabinoids and endocannabinoid‐like mediators might be a valuable option for treating stress‐related neuropsychiatric symptoms.
PDF
