Cannabinoid receptor-interacting protein 1a modulates CB1 receptor signaling and regulation.

“Cannabinoid CB1 receptors (CB1Rs) mediate the presynaptic effects of endocannabinoids in the central nervous system (CNS) and most behavioral effects of exogenous cannabinoids.

Cannabinoid receptor-interacting protein 1a (CRIP1a) binds to the CB1R C-terminus and can attenuate constitutive CB1R-mediated inhibition of Ca(2+) channel activity.

We now demonstrate cellular colocalization of CRIP1a at neuronal elements in the CNS and show that CRIP1a inhibits both constitutive and agonist-stimulated CB1R-mediated guanine nucleotide-binding regulatory protein (G-protein) activity.

These results confirm that CRIP1a inhibits constitutive CB1R activity and demonstrate that CRIP1a can also inhibit agonist-stimulated CB1R signaling and downregulation of CB1Rs. Thus, CRIP1a appears to act as a broad negative regulator of CB1R function.”

http://www.ncbi.nlm.nih.gov/pubmed/25657338

Modulatory effects by CB1 receptors on rat spinal locomotor networks after sustained application of agonists or antagonists.

“Sustained administration of cannabinoid agonists acting on neuronal CB1 receptors (CB1Rs) are proposed for treating spasticity and chronic pain…

Our data suggest that CB1Rs may control the circuit gateway regulating the inflow of sensory afferent inputs into the locomotor circuits, indicating a potential site of action for restricting peripheral signals disruptive for locomotor activity.”

Endocannabinoid signaling in female reproductive events: a potential therapeutic target?

“Nearly 30 years after the discovery in 1964 of the psychoactive ingredient of cannabis (Cannabis sativa), Δ9-tetrahydrocannabinol, its endogenous counterparts were discovered and collectively termed endocannabinoids (eCBs): N-arachidonoylethanolamine (anandamide) in 1992 and 2-arachidonoylglycerol in 1995.

Since then, intense research has identified additional eCBs and an ensemble of proteins that bind, synthesize and degrade them, the so-called eCB system.

Altogether, these new compounds have been recognized as key mediators of several aspects of human pathophysiology, and in particular of female fertility.

Here, the main features of the eCB system are presented, in order to put in a better perspective the relevance of eCB signaling in virtually all steps of human reproduction and to highlight emerging hopes that elements of this system might indeed become novel targets to combat fertility problems.”

http://www.ncbi.nlm.nih.gov/pubmed/26126134

Roles for the endocannabinoid system in ethanol-motivated behavior.

“Alcohol use disorder represents a significant human health problem that leads to substantial loss of human life and financial cost to society. Currently available treatment options do not adequately address this human health problem, and thus, additional therapies are desperately needed.

The endocannabinoid system has been shown, using animal models, to modulate ethanol-motivated behavior, and it has also been demonstrated that chronic ethanol exposure can have potentially long-lasting effects on the endocannabinoid system.

For example, chronic exposure to ethanol, in either cell culture or preclinical rodent models, causes an increase in endocannabinoid levels that results in down-regulation of the cannabinoid receptor 1 (CB1) and uncoupling of this receptor from downstream G protein signaling pathways.

Using positron emission tomography (PET), similar down-regulation of CB1 has been noted in multiple regions of the brain in human alcoholic patients.

In rodents, treatment with the CB1 inverse agonist SR141716A (Rimonabant), or genetic deletion of CB1 leads to a reduction in voluntary ethanol drinking, ethanol-stimulated dopamine release in the nucleus accumbens, operant self-administration of ethanol, sensitization to the locomotor effects of ethanol, and reinstatement/relapse of ethanol-motivated behavior.

Although the clinical utility of Rimonabant or other antagonists/inverse agonists for CB1 is limited due to negative neuropsychiatric side effects, negative allosteric modulators of CB1 and inhibitors of endocannabinoid catabolism represent therapeutic targets worthy of additional examination.”

Ultralow doses of cannabinoid drugs protect the mouse brain from inflammation-induced cognitive damage.

“In our previous studies, we found that a single ultralow dose of tetrahydrocannabinol (THC)… protects the brain from different insults that cause cognitive deficits.

Because various insults may trigger a neuroinflammatory response that leads to secondary damage to the brain, the current study tested whether this extremely low dose of THC could protect the brain from inflammation-induced cognitive deficits…

Our results suggest that an ultralow dose of THC that lacks any psychotrophic activity protects the brain from neuroinflammation-induced cognitive damage and might be used as an effective drug for the treatment of neuroinflammatory conditions, including neurodegenerative diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/25042014

Colocalization of cannabinoid receptor 1 with somatostatin and neuronal nitric oxide synthase in rat brain hippocampus.

“Somatostatin (SST), a growth hormone inhibitory peptide, is expressed in different parts of the brain and functions as a neurotransmitter and neuromodulator. In the central nervous system (CNS), SST inhibits Ca2+ influx and regulates neuronal excitability in the hippocampus, the brain region which plays a major role in seizure, as well as cognitive and memory function.

Much like SST, cannabinoid receptor 1 (CB1 receptor) is also widely distributed in the CNS, associated with memory function ad exerts inhibitory effects on seizure.

It is unknown whether overlapping functional activities of SST and CB1 receptor are also associated with coexpression in the hippocampus.

In the present study, we determined the colocalization between SST and CB1 receptor in adult rat brain hippocampus. In the CNS, the majority of SST positive interneurons coexpress neuronal nitric oxide synthase (nNOS). Accordingly, colocalization studies were also performed to determine whether nNOS positive neurons display comparable colocalization with CB1 receptor.

The findings suggested that SST and nNOS are expressed in most interneurons whereas CB1 receptor is present in both interneurons and projection neurons in hippocampal regions. The distinct neuronal populations either expressing CB1 receptor, SST and nNOS alone or colocalization were observed in a region specific manner.

Taken together, the observations described here anticipate the possibility of crosstalk between somatostatin subtypes and CB1 receptor in regulation of physiological activities in the hippocampus.”

http://www.ncbi.nlm.nih.gov/pubmed/26115586

Psychological and social sequelae of cannabis and other illicit drug use by young people: a systematic review of longitudinal, general population studies.

“Use of illicit drugs, particularly cannabis, by young people is widespread and is associated with several types of psychological and social harm. These relations might not be causal. Causal relations would suggest that recreational drug use is a substantial public health problem…

All these associations seemed to be explicable in terms of non-causal mechanisms.

Available evidence does not strongly support an important causal relation between cannabis use by young people and psychosocial harm…

The lack of evidence of robust causal relations prevents the attribution of public health detriments to illicit drug use.”

http://www.ncbi.nlm.nih.gov/pubmed/15145631

Biomedical benefits of cannabinoids?

“Cannabinoids appear to be of therapeutic value as antiemetics, antispasmodics, analgesics and appetite stimulants and may have potential uses in epilepsy, glaucoma and asthma.

This paper reviews the clinical trials which have been carried out with cannabinoids including Δ⁹-tetrahydrocannabinol (THC) and synthetic cannabinoids such as nabilone and levonantradol, and discusses the advantages and adverse effects of cannabinoids in clinical use.

The place of cannabinoids in modern medicine remains to be properly evaluated, but present evidence suggests that they could be valuable, particularly as adjuvants, for symptom control in a range of conditions for which standard drugs are not fully satisfactory.”

The endocannabinoid anandamide during lactation increases body fat content and CB1 receptor levels in mice adipose tissue.

“Type 1 cannabinoid receptors (CB1R) modulate energy balance; thus, their premature activation may result in altered physiology of tissues involved in such a function.

Activation of CB1R mainly occurs after binding to the endocannabinoid Anandamide (AEA).

The objective of this study was to evaluate the effects of AEA treatment during lactation on epididymal and body fat content, in addition to CB1R protein level at weaning.

This in vivo study shows for the first time that a progressive increase in body fat accumulation can be programmed in early stages of life by oral treatment with the endocannabinoid AEA, a fact associated with an increased amount of epididymal fat pads and a higher expression of CB1R in this tissue.”

http://www.ncbi.nlm.nih.gov/pubmed/26098446

Topical cannabinoid receptor 1 agonist attenuates the cutaneous inflammatory responses in oxazolone-induced atopic dermatitis model.

“This study was performed to investigate the effects of CBR agonists on skin inflammation, using acute and chronic inflammation animal models.

All of the results suggest that topical application of CB1R-specific agonist can be beneficial for alleviating the inflammatory symptoms in chronic skin diseases, including atopic dermatitis.”

http://www.ncbi.nlm.nih.gov/pubmed/26095080