Cannabinoid Type 2 Receptors Mediate a Cell Type-Specific Plasticity in the Hippocampus

Posted on May 2, 2016 by David

“Endocannabinoids (eCBs) exert major control over neuronal activity by activating cannabinoid receptors (CBRs).

The functionality of the eCB system is primarily ascribed to the well-documented retrograde activation of presynaptic CB₁Rs.

We find that action potential-driven eCB release leads to a long-lasting membrane potential hyperpolarization in hippocampal principal cells that is independent of CB₁Rs.

The hyperpolarization, which is specific to CA3 and CA2 pyramidal cells (PCs), depends on the activation of neuronal CB₂Rs, as shown by a combined pharmacogenetic and immunohistochemical approach.

Upon activation, they modulate the activity of the sodium-bicarbonate co-transporter, leading to a hyperpolarization of the neuron.

CB₂R activation occurred in a purely self-regulatory manner, robustly altered the input/output function of CA3 PCs, and modulated gamma oscillations in vivo.

To conclude, we describe a cell type-specific plasticity mechanism in the hippocampus that provides evidence for the neuronal expression of CB₂Rs and emphasizes their importance in basic neuronal transmission.”

http://www.cell.com/neuron/abstract/S0896-6273(16)30025-3

Cannabidiol attenuates catalepsy induced by distinct pharmacological mechanisms via 5-HT1A receptor activation in mice.

Posted on May 2, 2016 by David

“Cannabidiol (CBD) is a non-psychotomimetic compound from Cannabis sativa plant that produces antipsychotic effects in rodents and humans.

It also reverses L-dopa-induced psychotic symptoms and improves motor function in Parkinson’s patients. This latter effect raised the possibility that CBD could have beneficial effects on motor related striatal disorders.

To investigate this possibility we evaluated if CBD would prevent catalepsy induced by drugs with distinct pharmacological mechanisms.

These findings indicate that CBD can attenuate catalepsy caused by different mechanisms (D2 blockade, NOS inhibition and CB1 agonism) via 5-HT1A receptor activation, suggesting that it could be useful in the treatment of striatal disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/23791616

Cannabidiol attenuates haloperidol-induced catalepsy and c-Fos protein expression in the dorsolateral striatum via 5-HT1A receptors in mice.

Posted on May 2, 2016 by David

“Cannabidiol (CBD) is a major non-psychoactive compound from Cannabis sativa plant.

Given that CBD reduces psychotic symptoms without inducing extrapyramidal motor side-effects in animal models and schizophrenia patients, it has been proposed to act as an atypical antipsychotic.

In addition, CBD reduced catalepsy induced by drugs with distinct pharmacological mechanisms, including the typical antipsychotic haloperidol.

Altogether, these results suggest that CBD acts in the dorsal striatum to improve haloperidol-induced catalepsy via postsynaptic 5-HT_1A receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27131780

ENDOCANNABINOID SYSTEM: A multi-facet therapeutic target.

Posted on April 19, 2016 by David

Image result for Curr Clin Pharmacol.

“Cannabis sativa is also popularly known as marijuana. It is being cultivated and used by man for recreational and medicinal purposes from many centuries.

Study of cannabinoids was at bay for very long time and its therapeutic value could not be adequately harnessed due to its legal status as proscribed drug in most of the countries.

The research of drugs acting on endocannabinoid system has seen many ups and down in recent past. Presently, it is known that endocannabinoids has role in pathology of many disorders and they also serve “protective role” in many medical conditions.

Several diseases like emesis, pain, inflammation, multiple sclerosis, anorexia, epilepsy, glaucoma, schizophrenia, cardiovascular disorders, cancer, obesity, metabolic syndrome related diseases, Parkinson’s disease, Huntington’s disease, Alzheimer’s disease and Tourette’s syndrome could possibly be treated by drugs modulating endocannabinoid system.

Presently, cannabinoid receptor agonists like nabilone and dronabinol are used for reducing the chemotherapy induced vomiting. Sativex (cannabidiol and THC combination) is approved in the UK, Spain and New Zealand to treat spasticity due to multiple sclerosis. In US it is under investigation for cancer pain, another drug Epidiolex (cannabidiol) is also under investigation in US for childhood seizures. Rimonabant, CB1 receptor antagonist appeared as a promising anti-obesity drug during clinical trials but it also exhibited remarkable psychiatric side effect profile. Due to which the US Food and Drug Administration did not approve Rimonabant in US. It sale was also suspended across the EU in 2008.

Recent discontinuation of clinical trial related to FAAH inhibitor due to occurrence of serious adverse events in the participating subjects could be discouraging for the research fraternity. Despite of some mishaps in clinical trials related to drugs acting on endocannabinoid system, still lot of research is being carried out to explore and establish the therapeutic targets for both cannabinoid receptor agonists and antagonists.

One challenge is to develop drugs that target only cannabinoid receptors in a particular tissue and another is to invent drugs that acts selectively on cannabinoid receptors located outside the blood brain barrier. Besides this, development of the suitable dosage forms with maximum efficacy and minimum adverse effects is also warranted.

Another angle to be introspected for therapeutic abilities of this group of drugs is non-CB1 and non-CB2 receptor targets for cannabinoids.

In order to successfully exploit the therapeutic potential of endocannabinoid system, it is imperative to further characterize the endocannabinoid system in terms of identification of the exact cellular location of cannabinoid receptors and their role as “protective” and “disease inducing substance”, time-dependent changes in the expression of cannabinoid receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27086601

Cannabis Use Linked to Better Social Skills in Psychosis

Posted on March 23, 2016 by David

“Psychosis patients who have used cannabis have greater premorbid social skills than patients with psychosis who have never used the drug, data from five European countries suggest.

Laura Ferraro, a PhD student in psychiatry at the University of Palermo, in Italy, and colleagues found that lifetime cannabis use was associated with significantly increased improvements in premorbid social adjustment among psychosis patients.”

http://www.medscape.com/viewarticle/860664

Peripubertal treatment with cannabidiol prevents the emergence of psychosis in an animal model of schizophrenia

Posted on February 10, 2016 by David

“Currently, the pharmacotherapy of schizophrenia is still associated with significant side effects and high rates of treatment resistance, causing a great deal of suffering to patients and their caregivers. Developing safe interventions able to prevent the emergence of full-blown psychosis would therefore represent a major advance.

Cannabidiol (CBD) is a non-psychotomimetic compound of Cannabis sativa that presents antipsychotic properties in animal models and humans.

However, despite the growing evidence of CBD’s neuroprotective effects and therapeutic application in schizophrenia, so far no study has addressed its potential as a preventive intervention.”

http://www.schres-journal.com/article/S0920-9964(16)30060-3/abstract

http://www.thctotalhealthcare.com/category/schizophrenia/

Therapeutic Potential of Cannabinoids in Psychosis.

Posted on February 8, 2016 by David

“Over recent years, the interest in the endocannabinoid system (ECS) as a new target for the treatment of schizophrenia has evolved.

The ECS represents one of the most relevant neurotransmitter systems in the brain and mainly fulfills a homeostatic role in terms of neurotransmission but also with respect to inflammatory processes.

Two main approaches to the modulation of endocannabinoid functioning have been chosen so far. First, the selective blockade or inverse agonism of the type 1 cannabinoid receptor has been tested for the improvement of acute psychotic symptoms, as well as for the improvement of cognitive functions in schizophrenia.

Second, the modulation of endocannabinoid levels by use of the phytocannabinoid cannabidiol and selective fatty acid amide hydrolase inhibitors has been proposed, and the antipsychotic properties of cannabidiol are currently being investigated in humans.

Unfortunately, for most of these trials that have focused on psychopathological and cognitive effects of cannabidiol, no published data are available. However, there is first evidence that cannabidiol may ameliorate psychotic symptoms with a superior side-effect profile compared with established antipsychotics.

In conclusion, several clinical trials targeting the ECS in acute schizophrenia have either been completed or are underway. Although publicly available results are currently limited, preliminary data indicate that selected compounds modulating the ECS may be effective in acute schizophrenia.

Nevertheless, so far, sample sizes of patients investigated are not sufficient to come to a final judgment, and no maintenance studies are available to ensure long-term efficacy and safety.”

http://www.ncbi.nlm.nih.gov/pubmed/26852073

http://www.thctotalhealthcare.com/category/schizophrenia/

Cannabidiol, neuroprotection and neuropsychiatric disorders.

Posted on February 5, 2016 by David

“Cannabidiol (CBD) is a non-psychotomimetic phytocannabinoid derived from Cannabis sativa.

It has possible therapeutic effects over a broad range of neuropsychiatric disorders.

CBD attenuates brain damage associated with neurodegenerative and/or ischemic conditions.

It also has positive effects on attenuating psychotic-, anxiety- and depressive-like behaviors.

Moreover, CBD affects synaptic plasticity and facilitates neurogenesis.

The mechanisms of these effects are still not entirely clear but seem to involve multiple pharmacological targets.

In the present review, we summarized the main biochemical and molecular mechanisms that have been associated with the therapeutic effects of CBD, focusing on their relevance to brain function, neuroprotection and neuropsychiatric disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/26845349

Cannabinoids for the Treatment of Schizophrenia: An Overview.

Posted on February 5, 2016 by David

“Δ9-tetrahydrocannabinol and its analogues are found to have particular application in psychiatry because of their antipsychotic properties suggesting a therapeutic use as neuroleptic agents in limiting psychotic diseases.

These treatments should not only aim to alleviate specific symptoms but also attempt to delay/arrest disease progression.

In the present review, we reported recent studies supporting the view that the cannabinoid signalling system is a key modulatory element in the activity of the striatum and temporal cortex that has been traditionally associated with psychosis and schizophrenia.

This idea is supported by different anatomical, electrophysiological, pharmacological and biochemical data.

Furthermore, these studies indicate that the cannabinoid system is impaired in different psychotic disorders, supporting the idea of developing novel pharmacotherapies with compounds that selectively target specific elements of the cannabinoid system.”

http://www.ncbi.nlm.nih.gov/pubmed/26845552

http://www.thctotalhealthcare.com/category/schizophrenia/

CB2 Cannabinoid Receptor Knockout in Mice Impairs Contextual Long-Term Memory and Enhances Spatial Working Memory.

Posted on January 29, 2016 by David

“Neurocognitive effects of cannabinoids have been extensively studied with a focus on CB1 cannabinoid receptors because CB1 receptors have been considered the major cannabinoid receptor in the nervous system. However, recent discoveries of CB2 cannabinoid receptors in the brain demand accurate determination of whether and how CB2 receptors are involved in the cognitive effects of cannabinoids.

CB2 cannabinoid receptors are primarily involved in immune functions, but also implicated in psychiatric disorders such as schizophrenia and depression. Here, we examined the effects of CB2 receptor knockout in mice on memory to determine the roles of CB2 receptors in modulating cognitive function.

Our results suggest that CB2 cannabinoid receptors play diverse roles in regulating memory depending on memory types and/or brain areas.”

http://www.ncbi.nlm.nih.gov/pubmed/26819779