Bidirectional Effects of Cannabidiol on Contextual Fear Memory Extinction

Posted on December 18, 2016 by David

“Cannabidiol (CBD) is the major non-psychotropic constituent of the Cannabis plant and has anxiolytic therapeutic potential.

Cannabidiol (CBD) has been established to have both acute and long-lasting effects to reduce fear memory expression.

We showed that under conditions of strong fear conditioning, CBD reduced contextual fear memory expression both acutely during the extinction session as well as later at a fear retention test.

This pattern of results is consistent with CBD enhancing contextual fear memory extinction when the initial conditioning is strong, but impairing extinction when conditioning is weak. This bidirectional effect of CBD may be related to stress levels induced by conditioning and evoked at retrieval during extinction, rather than the strength of the memory per se.

In summary, CBD had bidirectional effects on the extinction of contextual fear conditioning, depending on the nature of the initial fear conditioning. Nevertheless, in the more translationally-relevant stronger conditioning setting, CBD both acutely inhibited fear expression and enhanced extinction to produce longer lasting reductions in fear.

These observations provide further support for the potential translational use of CBD in conditions such as posttraumatic stress disorder and specific phobias.”

http://journal.frontiersin.org/article/10.3389/fphar.2016.00493/full?utm_source=S-TWT&utm_medium=SNET&utm_campaign=ECO_FPHAR_XXXXXXXX_auto-dlvrit%0A

Cannabidiol Regulation of Learned Fear: Implications for Treating Anxiety-Related Disorders.

Posted on December 12, 2016 by David

“Anxiety and trauma-related disorders are psychiatric diseases with a lifetime prevalence of up to 25%. Phobias and post-traumatic stress disorder (PTSD) are characterized by abnormal and persistent memories of fear-related contexts and cues. The effects of psychological treatments such as exposure therapy are often only temporary and medications can be ineffective and have adverse side effects.

Growing evidence from human and animal studies indicates that cannabidiol, the main non-psychotomimetic phytocannabinoid present in Cannabis sativa, alleviates anxiety in paradigms assessing innate fear.

More recently, the effects of cannabidiol on learned fear have been investigated in preclinical studies with translational relevance for phobias and PTSD.

Here we review the findings from these studies, with an emphasis on cannabidiol regulation of contextual fear.

The evidence indicates that cannabidiol reduces learned fear in different ways: (1) cannabidiol decreases fear expression acutely, (2) cannabidiol disrupts memory reconsolidation, leading to sustained fear attenuation upon memory retrieval, and (3) cannabidiol enhances extinction, the psychological process by which exposure therapy inhibits learned fear.

We also present novel data on cannabidiol regulation of learned fear related to explicit cues, which indicates that auditory fear expression is also reduced acutely by cannabidiol.

We conclude by outlining future directions for research to elucidate the neural circuit, psychological, cellular, and molecular mechanisms underlying the regulation of fear memory processing by cannabidiol.

This line of investigation may lead to the development of cannabidiol as a novel therapeutic approach for treating anxiety and trauma-related disorders such as phobias and PTSD in the future.”

https://www.ncbi.nlm.nih.gov/pubmed/27932983

PTSD: from neurobiology to pharmacological treatments.

Posted on November 13, 2016 by David

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“Posttraumatic stress disorder (PTSD) is a chronic debilitating psychiatric disorder characterized by symptoms of re-experience, avoidance, and hyperarousal that can arise immediately or many years after exposure to a traumatic event and injury. Although extensive research has been done over the past 30 years, the etiology of PTSD remains largely unknown. Several neurobiological systems have been implicated in the pathophysiology and vulnerability for developing PTSD; however, first-line pharmacotherapies are limited. Less than 30% achieve full remission, and even then, approved pharmacological treatments often take weeks for therapeutic effect. This article aims to review the pathophysiology of PTSD within multiple neurobiological systems and how these mechanisms are used as pharmacologic targets of treatment, as well as their potential for future targets of intervention.”

https://www.ncbi.nlm.nih.gov/pubmed/27837583

Targeting the Endocannabinoid System in Psychiatric Illness.

Posted on November 5, 2016 by David

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“Prevalence of psychiatric disorders continues to rise globally, yet remission rates and patient outcome remain less than ideal. As a result, novel treatment approaches for these disorders are necessary to decrease societal economic burden, as well as increase individual functioning.

The recent discovery of the endocannabinoid system has provided an outlet for further research into its role in psychiatric disorders, because efficacy of targeted treatments have been demonstrated in medical illnesses, including cancers, neuropathic pain, and multiple sclerosis.

The present review will investigate the role of the endocannabinoid system in psychiatric disorders, specifically schizophrenia, depressive, anxiety, and posttraumatic stress disorders, as well as attention-deficit hyperactivity disorder.

Controversy remains in prescribing medicinal cannabinoid treatments due to the fear of adverse effects. However, one must consider all potential limitations when determining the safety and tolerability of cannabinoid products, specifically cannabinoid content (ie, Δ-tetrahydrocannabinol vs cannabidiol) as well as study design.

The potential efficacy of cannabinoid treatments in the psychiatric population is an emerging topic of interest that provides potential value going forward in medicine.”

https://www.ncbi.nlm.nih.gov/pubmed/27811555

Effectiveness of Cannabidiol Oil for Pediatric Anxiety and Insomnia as Part of Posttraumatic Stress Disorder: A Case Report.

Posted on October 23, 2016 by David

“Anxiety and sleep disorders are often the result of posttraumatic stress disorder and can contribute to an impaired ability to focus and to demonstration of oppositional behaviors.

CASE PRESENTATION:

These symptoms were present in our patient, a ten-year-old girl who was sexually abused and had minimal parental supervision as a young child under the age of five. Pharmaceutical medications provided partial relief, but results were not long-lasting, and there were major side effects. A trial of cannabidiol oil resulted in a maintained decrease in anxiety and a steady improvement in the quality and quantity of the patient’s sleep.

DISCUSSION:

Cannabidiol oil, an increasingly popular treatment of anxiety and sleep issues, has been documented as being an effective alternative to pharmaceutical medications. This case study provides clinical data that support the use of cannabidiol oil as a safe treatment for reducing anxiety and improving sleep in a young girl with posttraumatic stress disorder.”

https://www.ncbi.nlm.nih.gov/pubmed/27768570

Chronic stress leads to epigenetic dysregulation of neuropeptide-Y and cannabinoid CB1 receptor in the mouse cingulate cortex.

Posted on October 18, 2016 by David

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“Persistent stress triggers a variety of mechanisms, which may ultimately lead to the occurrence of anxiety- and depression-related disorders.

Epigenetic modifications represent a mechanism by which chronic stress mediates long-term effects. Here, we analyzed brain tissue from mice exposed to chronic unpredictable stress (CUS), which induced impaired emotional and nociceptive behaviors.

As endocannabinoid (eCB) and neuropeptide-Y (Npy) systems modulate emotional processes, we hypothesized that CUS may affect these systems through epigenetic mechanisms.

We found reduced Npy expression and Npy type 1 receptor (Npy1r) signaling, and decreased expression of the cannabinoid type 1 receptor (CB1) in the cingulate cortex of CUS mice specifically in low CB1-expressing neurons.

Our findings suggest that epigenetic alterations in the Npy and CB1 genes represent one of the potential mechanisms contributing to the emotional imbalance induced by CUS in mice, and that the Npy and eCB systems may represent therapeutic targets for the treatment of psychopathologies associated with or triggered by chronic stress states.”

https://www.ncbi.nlm.nih.gov/pubmed/27737789

Cannabinoid CB1 receptors in distinct circuits of the extended amygdala determine fear responsiveness to unpredictable threat.

Posted on October 5, 2016 by David

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“The brain circuits underlying behavioral fear have been extensively studied over the last decades.

Here, we show that the endocannabinoid system acting in synaptic circuits of the extended amygdala can explain the fear response profile during exposure to unpredictable threat.

Using fear training with predictable or unpredictable cues in mice, combined with local and cell-type-specific deficiency and rescue of cannabinoid type 1 (CB1) receptors, we found that presynaptic CB1 receptors on distinct amygdala projections to bed nucleus of the stria terminalis (BNST) are both necessary and sufficient for the shift from phasic to sustained fear in response to an unpredictable threat.

These results thereby identify the causal role of a defined protein in a distinct brain pathway for the temporal development of a sustained state of anxious apprehension during unpredictability of environmental influences, reminiscent of anxiety symptoms in humans.”

https://www.ncbi.nlm.nih.gov/pubmed/27698427

Endocannabinoid signaling in social functioning: an RDoC perspective.

Posted on September 28, 2016 by David

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“Core deficits in social functioning are associated with various neuropsychiatric and neurodevelopmental disorders, yet biomarker identification and the development of effective pharmacological interventions has been limited.

Recent data suggest the intriguing possibility that endogenous cannabinoids, a class of lipid neuromodulators generally implicated in the regulation of neurotransmitter release, may contribute to species-typical social functioning.

Systematic study of the endogenous cannabinoid signaling could, therefore, yield novel approaches to understand the neurobiological underpinnings of atypical social functioning.

This article provides a critical review of the major components of the endogenous cannabinoid system (for example, primary receptors and effectors-Δ9-tetrahydrocannabinol, cannabidiol, anandamide and 2-arachidonoylglycerol) and the contributions of cannabinoid signaling to social functioning.

Data are evaluated in the context of Research Domain Criteria constructs (for example, anxiety, chronic stress, reward learning, motivation, declarative and working memory, affiliation and attachment, and social communication) to enable interrogation of endogenous cannabinoid signaling in social functioning across diagnostic categories.

The empirical evidence reviewed strongly supports the role for dysregulated cannabinoid signaling in the pathophysiology of social functioning deficits observed in brain disorders, such as autism spectrum disorder, schizophrenia, major depressive disorder, posttraumatic stress disorder and bipolar disorder.

Moreover, these findings indicate that the endogenous cannabinoid system holds exceptional promise as a biological marker of, and potential treatment target for, neuropsychiatric and neurodevelopmental disorders characterized by impairments in social functioning.”

https://www.ncbi.nlm.nih.gov/pubmed/27676446

Don’t Worry, Be Happy: Endocannabinoids and Cannabis at the Intersection of Stress and Reward.

Posted on September 14, 2016 by David

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“Cannabis enables and enhances the subjective sense of well-being by stimulating the endocannabinoid system (ECS), which plays a key role in modulating the response to stress, reward, and their interactions.

The recent shift toward legalization of medical or recreational cannabis has renewed interest in investigating the physiological role of the ECS as well as the potential health effects, both adverse and beneficial, of cannabis.

Here we review our current understanding of the ECS and its complex physiological roles.

We discuss the implications of this understanding vis-á-vis the ECS’s modulation of stress and reward and its relevance to mental disorders in which these processes are disrupted (i.e., addiction, depression, posttraumatic stress disorder, schizophrenia), along with the therapeutic potential of strategies to manipulate the ECS for these conditions.”

http://www.ncbi.nlm.nih.gov/pubmed/27618739

Modulation of Long-Term Potentiation of Cortico-Amygdala Synaptic Responses and Auditory Fear Memory by Dietary Polyunsaturated Fatty Acid.

Posted on September 8, 2016 by David

“Converging evidence suggests that an imbalance of ω3 to ω6 polyunsaturated fatty acid (PUFA) in the brain is involved in mental illnesses such as anxiety disorders.

We previously reported that the dietary ratio of ω3 to ω6 PUFA alters this ratio in the brain, and influences contextual fear memory.

In addition to behavioral change, enhancement of cannabinoid CB1 receptor-mediated short-term synaptic plasticity and facilitation of the agonist sensitivity of CB1 receptors have been observed in excitatory synaptic responses in the basolateral nucleus of the amygdala (BLA).

These results suggest that the balance of ω3 to ω6 PUFA has an impact on fear memory and cortico-amygdala synaptic plasticity, both in a CB1 receptor-dependent manner.”

http://www.ncbi.nlm.nih.gov/pubmed/27601985

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