Tag Archives: CB(1) and CB(2) receptors

Cannabinoid Receptor 2-Mediated Attenuation of CXCR4-Tropic HIV Infection in Primary CD4+ T Cells

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“Agents that activate cannabinoid receptor pathways have been tested as treatments for cachexia, nausea or neuropathic pain in HIV-1/AIDS patients… Cannabinoid agonists activate the CB1R and CB2R cannabinoid receptors…

Cannabinoid agonists are currently under investigation for the treatment of AIDS-associated cachexia, nausea, and neuropathic pain. One such drug, dronabinol (Δ9-THC; Marinol®), has won Food and Drug Administration (FDA) approval for treatment of HIV-associated anorexia. Additionally, the prescription of smoked or ingested cannabis (marijuana) for treatment of AIDS-related symptoms has been approved…. Despite the use of cannabinoids by HIV/AIDS patients, few studies have investigated the impact of such drugs in regard to viral pathogenesis or immune regulation…

….Indeed, both smoked marijuana and dronabinol were reported to increase total CD4+ T cell number and naïve T cell number over a 21-day period. A decrease in viral load was also observed in these patients. Similarly, in SIV infected rhesus macaques, Δ9-THC exposure reduced viral load and CD4+ T cell depletion, significantly increasing animal survival over an 11 month period.

. Our findings suggest that CB2R activation in CD4+ T cells can inhibit actin reorganization and impair productive infection following cell-free or cell-associated viral acquisition of CXCR4-tropic HIV-1 in resting cells.

Therefore, the clinical use of CB2R agonists in the treatment of AIDS symptoms may also exert beneficial adjunctive antiviral effects against CXCR4-tropic viruses in late stages of HIV-1 infection.

Further study of cannabinoids and other neuroendocrine regulators that selectively modulate immune function may result in the discovery of new anti-viral drugs that can also mitigate AIDS-associated symptoms.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3309010/

Proof of Concept Trial of Dronabinol in Obstructive Sleep Apnea

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“… Δ9-TetraHydroCannabinol (Δ9THC) stabilizes autonomic output during sleep, reduces spontaneous sleep-disordered breathing, and blocks serotonin-induced exacerbation of sleep apnea. On this basis, we examined the safety, tolerability, and efficacy of dronabinol (Δ9THC), an exogenous Cannabinoid type 1 and type 2 (CB1 and CB2) receptor agonist in patients with Obstructive Sleep Apnea (OSA)…

Conclusion: Dronabinol treatment is safe and well-tolerated in OSA patients at doses of 2.5–10mg daily and significantly reduces AHI in the short-term. These findings should be confirmed in a larger study in order to identify sub-populations with OSA that may benefit from cannabimimetic pharmacologic therapy…

This proof of concept study demonstrates that dronabinol is safe, well-tolerated, and reduces AHI by approximately a third over 3 weeks of oral administration. Dronabinol treatment may be a viable alternative or adjunctive therapy in selected patients with OSA.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3550518/

Cannabinoids ameliorate impairments induced by chronic stress to synaptic plasticity and short-term memory.

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“Repeated stress is one of the environmental factors that precipitates and exacerbates mental illnesses like depression and anxiety as well as cognitive impairments. We have previously shown that cannabinoids can prevent the effects of acute stress on learning and memory.

Here we aimed to find whether chronic cannabinoid treatment would alleviate the long-term effects of exposure to chronic restraint stress on memory and plasticity as well as on behavioral and neuroendocrine measures of anxiety and depression. Late adolescence rats were exposed to chronic restraint stress for two weeks followed each day by systemic treatment with vehicle or with the CB1/2 receptor agonist WIN55,212-2 (1.2 mg/kg). Thirty days after the last exposure to stress, rats demonstrated impaired long-term potentiation (LTP) in the ventral subiculum (vSub)-nucleus accumbens (NAc) pathway, impaired performance in the prefrontal cortex (PFC)-dependent object recognition task and the hippocampal-dependent spatial version of this task, increased anxiety levels, and significantly reduced expression of glucocorticoid receptors (GRs) in the amygdala, hippocampus, PFC and NAc. Chronic WIN55,212-2 administration prevented the stress-induced impairment in LTP levels and in the spatial task, with no effect on stress-induced alterations in unconditioned anxiety levels or GR levels. The CB1 antagonist AM251 (0.3 mg/kg) prevented the ameliorating effects of WIN55,212-2 on LTP and short-term memory. Hence, the beneficial effects of WIN55,212-2 on memory and plasticity are mediated by CB1 receptors and are not mediated by alterations in GR levels in the brain areas tested.

 Our findings suggest that cannabinoid receptor activation could represent a novel approach to the treatment of cognitive deficits that accompany a variety of stress-related neuropsychiatric disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/23426383

[Marihuana and cannabinoids as medicaments].

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“Biological activity of cannabinoids is caused by binding to two cannabinoid receptors CB1 and CB2. Psychoactive is not only tetrahydrocannabinol (THC) but also: cannabidiol, cannabigerol or cannabichromen. Formerly, the usefulness of hemp was assessed in the relation to temporary appeasement of the symptoms of some ailments as nausea or vomiting.

 Present discoveries indicates that cannabis-based drugs has shown ability to alleviate of autoimmunological disorders such as: Multiple sclerosis (MS), Rheumatoid arthritis (RA) or inflammatory bowel disease. Another studies indicates that cannabinoids play role in treatment of neurological disorders like Alzheimer disease or Amyotrophic lateral sclerosis (ALS) or even can reduce spreading of tumor cells.

 Cannabinoids stand out high safety profile considering acute toxicity, it is low possibility of deadly overdosing and side-effects are comprise in range of tolerated side-effects of other medications.

In some countries marinol and nabilone are used as anti vomiting and nausea drug. First cannabis-based drug containg naturally occurring cannabinoids is Sativex. Sativex is delivered in an mucosal spray for patients suffering from spasticity in MS, pain relevant with cancer and neuropathic pain of various origin. Despite the relatively low acute toxicity of cannabinoids they should be avoid in patients with psychotic disorders, pregnant or breastfeeding woman. Cannabinoids prolong a time of reaction and decrease power of concentration that’s why driving any vehicles is forbidden.

 Cannabis side-effects varies and depend from several factors like administrated dose, rout of administration and present state of mind. After sudden break from long-lasting use, withdrawal symptoms can appear, although they entirely disappear after a week or two.”

http://www.ncbi.nlm.nih.gov/pubmed/23421098

Role of cannabinoid and vanilloid receptors in invasion of human breast carcinoma cells.

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“It is known that the diversified effects of cannabinoid on the fate of carcinoma cells are mediated predominantly through receptors. However, little is known about the effects of the individual activities of cannabinoid and noncannabinoid receptors. Here we investigate the role of cannabinoid receptor (CB) 1, CB2, and transient receptor potential vanilloid type 1 in cell proliferation and invasion patterns in the MDA-MB-231 cell line.

Our results showed that activation of CB1 and vanilloid receptors by methanandamide, a nonselective agonist, and arachidonyl-2′-choloroethylamide (ACEA) and N-oleoyldopamine, selective agonists, reduced invasion of MDA-MB-231 cells at pharmacological concentrations. Accordingly, CB1 activation resulted in decreased expression of matrix metalloproteinase (MMP) 2. On the other hand, administration of a CB2 agonist (CB65) increased cell invasion and expression of MMP2. The data obtained from MTT assay did not show any correlation between reduced invasion and cytotoxic effects of drugs. In addition, the level of vascular endothelial growth factor was significantly reduced in treatment with (R)-(+)-methanandamide, ACEA, CB65, and AM251 (a potent agonist for GPR55 and selective antagonist of CB1) compared with control. Elevated expression of cyclooxygenase-2 was observed in all of the MDA-MB-231 cells treated with agonists.

These results underline the influence of cannabinoid and vanilloid receptors on the invasiveness of MDA-MB-231 human breast carcinoma cells.”

http://www.ncbi.nlm.nih.gov/pubmed/23394450

The pharmacologic and clinical effects of medical cannabis.

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“Cannabis, or marijuana, has been used for medicinal purposes for many years. Several types of cannabinoid medicines are available in the United States and Canada. Dronabinol (schedule III), nabilone (schedule II), and nabiximols (not U.S. Food and Drug Administration approved) are cannabis-derived pharmaceuticals.

Medical cannabis or medical marijuana, a leafy plant cultivated for the production of its leaves and flowering tops, is a schedule I drug, but patients obtain it through cannabis dispensaries and statewide programs. The effect that cannabinoid compounds have on the cannabinoid receptors (CB(1) and CB(2) ) found in the brain can create varying pharmacologic responses based on formulation and patient characteristics. The cannabinoid Δ(9) -tetrahydrocannabinol has been determined to have the primary psychoactive effects; the effects of several other key cannabinoid compounds have yet to be fully elucidated. Dronabinol and nabilone are indicated for the treatment of nausea and vomiting associated with cancer chemotherapy and of anorexia associated with weight loss in patients with acquired immune deficiency syndrome. However, pain and muscle spasms are the most common reasons that medical cannabis is being recommended.

Studies of medical cannabis show significant improvement in various types of pain and muscle spasticity. Reported adverse effects are typically not serious, with the most common being dizziness. Safety concerns regarding cannabis include the increased risk of developing schizophrenia with adolescent use, impairments in memory and cognition, accidental pediatric ingestions, and lack of safety packaging for medical cannabis formulations. This article will describe the pharmacology of cannabis, effects of various dosage formulations, therapeutics benefits and risks of cannabis for pain and muscle spasm, and safety concerns of medical cannabis use.”

http://www.ncbi.nlm.nih.gov/pubmed/23386598

Inhibition of endocannabinoid degradation in experimental endotoxemia reduces leukocyte adhesion and improves capillary perfusion in the gut.

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“Changes in leukocyte-endothelial and microvascular perfusion are hallmark events in inflammation. Thus, protection of the intestinal microcirculation represents a pivotal therapeutic target in systemic inflammation and sepsis.

The endocannabinoid system (ECS) modulates a number of critical homeostatic functions and has been associated with anti-inflammatory responses. Our study aimed to examine intestinal leukocyte adhesion and capillary perfusion following selective inhibition of the endocannabinoid degradation enzyme, fatty acid amide hydrolase (FAAH), in experimental sepsis (endotoxemia).

Conclusions: FAAH inhibition prevents the LPS-induced increase in leukocyte adhesion and improves the capillary perfusion of the gut. This might be mediated in part by CB2R activation.

Our study encourages further investigation into the therapeutic potential of drugs targeting the ECS in sepsis.”

More: http://www.ncbi.nlm.nih.gov/pubmed/23382309

Update on the Role of Cannabinoid Receptors after Ischemic Stroke

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“The endocannabinoid system is considered as a major modulator of the cerebral blood flow, neuroinflammation, and neuronal survival… Evidence from animal models and in vitro studies suggests a global protective role for cannabinoid receptors agonists in ischemic stroke…Given its potent anti-inflammatory activities on circulating leukocytes, the CB2 activation has been proven to produce protective effects against acute poststroke inflammation. In this paper, we will update evidence on different cannabinoid-triggered avenues to reduce inflammation and neuronal injury in acute ischemic stroke…

Synthetic cannabinoids have been also investigated in animal models showing an improvement of the ischemic injury in the liver, heart, and brain. Furthermore, phytocannabinoids have been also isolated from the Cannabis sativa. Since this plant contains about 80 different cannabinoids, a strong work is still needed to test all these active compounds. This delay in cannabinoid research might be also due to the very low dose of certain cannabinoids in the plant. Thus, since Δ9-tetrahydrocannabidiol (THC) and cannabidiol (CBD) represent up to 40% of the total cannabinoid mass, these compounds have been considered as the most active mediators…

The encouraging therapeutic results of this study are in partial contrast with previous case reports, suggesting a potential relationship between stroke and chronic cannabis abuse in young human beings…

We believe that the “cannabinoid” approach represents an interesting therapeutic strategy still requiring further validations to improve neurologic and inflammatory outcomes in ischemic stroke.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3337695/

Modulation of The Balance Between Cannabinoid CB1 and CB2 Receptor Activation During Cerebral Ischemic/Reperfusion Injury

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“A number of investigations have shown that CB2 receptor activation has anti-inflammatory therapeutic potential in various CNS diseases, such as multiple sclerosis, traumatic brain injury and Alzheimer’s disease. Because inflammatory responses have been shown to be important contributors to secondary injury following cerebral ischemia; the CB2 receptor has been investigated as a potential therapeutic target in stroke…

The most striking changes were obtained by combing a CB1 antagonist with a CB2 agonist. This combination elevated the cerebral blood flow during ischemia and reduced infarction by 75%…during cerebral ischemia/reperfusion injury, inhibition of CB1 receptor activation is protective while inhibition of CB2 receptor activation is detrimental.

 The greatest degree of neuroprotection was obtained by combining an inhibitor of CB1 activation with an exogenous CB2 agonist.

In conclusion, the results of this investigation demonstrate dynamic changes in the expression of CB1 and CB2 receptors during cerebral ischemic/reperfusion injury in mice. The effects of stimulation of these receptors on damage ischemia/reperfusion injury differed dramatically. Stimulation of the CB2 receptor was found to be neuroprotective, while inhibition of the CB1 receptor was also protective,too. The combination of a CB2 agonist and a CB1 antagonist provided the greatest degree of protection and indicated a synergistic effect derived from combining these agents. Therefore, changing the balance of stimulation of these receptors by endogenous cannabinoids may provide an important therapeutic strategy during stroke.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2577828/

Role of cannabinoids and endocannabinoids in cerebral ischemia

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“The human costs of stroke are very large and growing; it is the third largest cause of death in the United States and survivors are often faced with loss of ability to function independently. There is a large need for therapeutic approaches that act to protect neurons from the injury produced by ischemia and reperfusion… 

 Overall, the available data suggest that inhibition of CB1 receptor activation together with increased CB2 receptor activation produces beneficial effects.

These studies support the hypothesis that activation of the CB1 receptor by highly efficacious, exogenous agonists during the acute phase of ischemia decreases the likelihood of the occurrence of a detrimental event at the time of ischemia and thereby reduces the amount of infarction and neuronal death long-term… A protective role of the CB1 receptor is also supported by studies…

While it is possible that the ECS will be added to the long list of neuroprotective agents that show promise in animals and do not work in humans, there are a few reasons to be optimistic about this class of drugs. First, many of the other agents did not work because they do not cross the blood brain barrier. While the considerable lipophilicity of the cannabinoids poses its own set of problems, these drugs have no problems entering the brain. Second, the ECS is multifactorial and could “cover” multiple biochemical pathways in a single drug. Third, manipulations of the ECS has been shown to be beneficial in several preclinical models. Only time and further research will answer the most important question, are the cannabinoids of therapeutic benefit in humans suffering from stroke?”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2581413/