Predator threat stress promotes long lasting anxiety-like behaviors and modulates synaptophysin and CB1 receptors expression in brain areas associated with PTSD symptoms.

“Several studies have suggested that changes in hippocampal, prefrontal cortex and amygdaloid complex function are associated with the main symptoms of Posttraumatic Stress Disorder (PTSD). Predator exposure can mimic some aspects of PSTD such as hyperarousal and chronic anxiety…

 The present work evaluated whether the long lasting behavioral effects evoked by predator exposure are associated to long-term changes in the expression of the Cannabinoid receptor 1 (CB1) and the synaptic protein SYP in brain areas…

 Our results suggested that predator exposure causes long-lasting anxiogenic effects associated with hyperactivation of amygdaloid complex and modulation of CB1 receptor in brain areas related to PTSD symptoms.”

http://www.ncbi.nlm.nih.gov/pubmed/23178193

Role in Anxiety Behavior of the Endocannabinoid System in the Prefrontal Cortex

“Increasing evidence that low doses of cannabinoid agonists reduce anxiety-like behaviors in mice and rats is being reported, thus suggesting an anxiolytic role for the endogenous cannabinoid signaling. In line with this hypothesis, pharmacological agents that enhance the endogenous cannabinoid signaling exert anxiolytic-like actions…

  These findings support an anxiolytic role for physiological increases in AEA in the PFC, whereas more marked increases or decreases of this endocannabinoid might lead to an anxiogenic response due to TRPV1 stimulation or the lack of CB1 activation, respectively.”

http://cercor.oxfordjournals.org/content/18/6/1292.long

The endocannabinoid system in the processing of anxiety and fear and how CB1 receptors may modulate fear extinction.

“The endocannabinoid system recently emerged as an important modulator of many neuronal functions. Among them, the control of anxiety and acquired fear represents nowadays one of the most interesting fields of research. Despite contrasting results obtained by the use of cannabinoid receptor agonists in experimental animals, there is growing evidence that the physiological activation of the endocannabinoid system plays a central role in the control of basal anxiety levels and in the modulation of fear responses. This review will summarise recent data on the role of the endocannabinoid system in most commonly used tests of anxiety and in the processing of acquired fear, with particular attention to its involvement in fear extinction. Finally, a neurobiological model possibly able to implement the role of the endocannabinoid system in these processes will be proposed.”

http://www.ncbi.nlm.nih.gov/pubmed/17951068

Endocannabinoid system dysfunction in mood and related disorders.

“The endocannabinoid (EC) system is widely distributed throughout the brain and modulates many functions. It is involved in mood and related disorders, and its activity may be modified by exogenous cannabinoids. This article examines the therapeutic potential of cannabinoids in psychiatric disorders.

We propose (hypothesize) that the EC system, which is homoeostatic in cortical excitation and inhibition, is dysfunctional in mood and related disorders. Anandamide, tetrahydrocannabinol (THC) and cannabidiol (CBD) variously combine antidepressant, antipsychotic, anxiolytic, analgesic, anticonvulsant actions, suggesting a therapeutic potential in mood and related disorders. Currently, cannabinoids find a role in pain control. Post mortem and other studies report EC system abnormalities in depression, schizophrenia and suicide. Abnormalities in the cannabinoid-1 receptor (CNR1) gene that codes for cannabinoid-1 (CB1) receptors are reported in psychiatric disorders. However, efficacy trials of cannabinoids in psychiatric disorders are limited but offer some encouragement.

CONCLUSION:

Research is needed to elucidate the role of the EC system in psychiatric disorders and for clinical trials with THC, CBD and synthetic cannabinoids to assess their therapeutic potential.”

http://www.ncbi.nlm.nih.gov/pubmed/21916860

Expression pattern of the cannabinoid receptor genes in the frontal cortex of mood disorder patients and mice selectively bred for high and low fear.

“Although the endocannabinoid system (ECS) has been implicated in brain development and various psychiatric disorders, precise mechanisms of the ECS on mood and anxiety disorders remain unclear. Here, we have investigated developmental and disease-related expression pattern of the cannabinoid receptor 1 (CB1) and the cannabinoid receptor 2 (CB2) genes in the dorsolateral prefrontal cortex (PFC) of humans. Using mice selectively bred for high and low fear, we further investigated potential association between fear memory and the cannabinoid receptor expression in the brain…

 These results suggest that the CB1 in the PFC may play a significant role in regulating mood and anxiety symptoms. Our study demonstrates the advantage of utilizing data from postmortem brain tissue and a mouse model of fear to enhance our understanding of the role of the cannabinoid receptors in mood and anxiety disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/22534181

The endocannabinoid system and Alzheimer’s disease.

“The importance of the role of the endocannabinoid system (ECS) in neurodegenerative diseases has grown during the past few years. Mostly because of the high density and wide distribution of cannabinoid receptors of the CB(1) type in the central nervous system (CNS), much research focused on the function(s) that these receptors might play in pathophysiological conditions.

Our current understanding, however, points to much diverse roles for this system. In particular, other elements of the ECS, such as the fatty acid amide hydrolase (FAAH) or the CB(2) cannabinoid receptor are now considered as promising pharmacological targets for some diseases and new cannabinoids have been incorporated as therapeutic tools.

 Although still preliminary, recent reports suggest that the modulation of the ECS may constitute a novel approach for the treatment of Alzheimer’s disease (AD). Data obtained in vitro, as well as in animal models for this disease and in human samples seem to corroborate the notion that the activation of the ECS, through the use of agonists or by enhancing the endogenous cannabinoid tone, may induce beneficial effects on the evolution of this disease.”

http://www.ncbi.nlm.nih.gov/pubmed/17952652

The Cannabinoid CB2 Receptor as a Target for Inflammation-Dependent Neurodegeneration

“THE CANNABINOID CB2 RECEPTOR AS A BIORATIONAL TARGET FOR THE TREATMENT OF NEURODEGENERATION. The presence of CB2 receptors in microglia in the human Alzheimer’s diseased brain suggests that CB2 may provide a novel target for a range of neuropathologies.

 The first approved cannabinoid drugs were analogues of Δ9-tetrahydrocannabinol (Δ9-THC). Dronabinol is a natural isomer of THC that is found in the cannabis plant, and Marinol contains synthetic dronabinol. Marinol, and another analogue nabilone (Cesamet ) are used to prevent nausea and vomiting after treatment with anti-cancer medicines. More recently, GW-100 (Sativex) which combines nearly equal amounts of Δ9-THC and cannabidiol in a whole plant extract from cultivated cannabis, has been approved in Canada…

We conclude that the administration of CB2 agonists and antagonists may differentially alter microglia-dependent neuroinflammation. CB2 specific compounds have considerable therapeutic appeal over CB1 compounds, as the exclusive expression of CB2 on immune cells within the brain provides a highly specialised target, without the psychoactivity that plagues CB1 directed therapies.

In addition, CB2 activation appears to prevent or decrease microglial activation.

In a rodent model of Alzheimer’s disease microglial activation was completely prevented by administration of a selective CB2 agonist.”

http://www.ncbi.nlm.nih.gov/pubmed/18615177

Regulation of cannabinoid CB1 receptors in the central nervous system by chronic cannabinoids.

“The potential therapeutic benefits of certain cannabinoid-mediated effects, as well as the use of marijuana for its psychoactive properties, has raised interest in understanding the cellular adaptations produced by chronic administration of this class of drugs.”

http://www.ncbi.nlm.nih.gov/pubmed/14977366

Cannabinoid Receptor Type 1 Protects Nigrostriatal Dopaminergic Neurons against MPTP Neurotoxicity by Inhibiting Microglial Activation

“The present in vivo and in vitro findings clearly indicate that the CB1 receptor possesses anti-inflammatory properties and inhibits microglia-mediated oxidative stress.

 Our results collectively suggest that the cannabinoid system is beneficial for the treatment of Parkinson’s disease and other disorders associated with neuroinflammation and microglia-derived oxidative damage.

CB1 receptor is a useful pharmacological target for treating PD and other disorders associated with neuroinflammation and microglia-derived oxidative damage. ”

http://www.jimmunol.org/content/187/12/6508.long

Intact cannabinoid CB1 receptors in the Alzheimer’s disease cortex.

“The cannabinoid CB1 receptor has gained much attention as a potential pharmacotherapeutic target in various neurodegenerative diseases including Alzheimer’s disease (AD). Our study suggests that CB1 receptors are intact in AD and may play a role in preserving cognitive function.

 Therefore, CB1 receptors should be further assessed as a potential therapeutic target in AD.”

http://www.ncbi.nlm.nih.gov/pubmed/21034788