Background and purpose: Cannabidiol has been reported to act as an antagonist of cannabinoid agonists at type 1 cannabinoid receptors (CB1). We hypothesized that cannabidiol can inhibit cannabinoid agonist activity through negative allosteric modulation of CB1. Experimental approach: CB1 internalization, arrestin2 recruitment, and PLCβ3 and ERK1/2 phosphorylation, were quantified in HEK 293A cells heterologously expressing CB1 and in the STHdhQ7/Q7 cell model of striatal neurons endogenously expressing CB1. Cells were treated with 2- arachidonylglycerol or Δ9 -tetrahydrocannabinol alone and in combination with different concentrations of cannabidiol. Key results: Cannabidiol reduced the efficacy and potency of 2-arachidonylglycerol and Δ9 - tetrahydrocannabinol on PLCβ3- and ERK1/2-dependent...

The mechanism of action of cannabidiol, one of the major constituents of cannabis, is not well understood but a noncompetitive interaction with mu opioid receptors has been suggested on the basis of saturation binding experiments. The aim of the present study was to examine whether cannabidiol is an allosteric modulator at this receptor, using kinetic binding studies, which are particularly sensitive for the measurement of allosteric interactions at G protein-coupled receptors. In addition, we studied whether such a mechanism also extends to the delta opioid receptor. For comparison, (-)-Δ9 -tetrahydrocannabinol (THC; another major constituent of cannabis) and rimonabant (a cannabinoid CB1 receptor antagonist) were...

The whole plant extract of plant Sceletium tortuosum, plant native to South Africa, has been known traditionally to have mood enhancing and stimulant properties. These properties have been confirmed before by proving serotonin-uptake inhibition activity. A further confirmation by using CB1 receptor binding assay has been performed in this study. The unfermented alkaloid extract was proved to posses a higher activity to bind CB1 receptor compared to that of the fermented one. GC-MS analysis confirmed that unfermented alkoloid extract contain more alkaloids than the fermented one. The methanol extract was also more active than the fermented one, suggesting that non-alkaloid compounds in this extract...

Abstract Investigation of the cannabinoid system in a vertebrate group phylogenetically distant from mammals might improve understanding of its physiological role. Thus, in the present study, the distribution of the cannabinoid CB1 receptor has been investigated in the brain of Xenopus laevis (anuran amphibians) by immunohistochemistry, using both light and confocal laser-scanning microscopy. Immunostained neuronal perikarya and terminals were found in the olfactory bulb, dorsal and medial pallium, striatum, and amygdala. Varicosities and nerve terminals containing CB1-like immunoreactivity were also seen in the thalamus and hypothalamus. A number of stained cells were observed in the pars distalis of the pituitary gland. Positive nerve fibers...

Abstract In the last 25 years data has grown exponentially dealing with the discovery of the endocannabinoid system consisting of specific cannabinoid receptors, their endogenous ligands, and enzymatic systems of their biosynthesis and degradation. Progress is being made in the development of novel agonists and antagonists with receptor subtype selectivity which should help in providing a greater understanding of the physiological role of the endocannabinoid system and perhaps also in a broad number of pathologies. This could lead to advances with important therapeutic potential of drugs modulating activity of endocannabinoid system as hypnotics, analgesics, antiemetics, antiasthmatics, antihypertensives, immunomodulatory drugs, antiphlogistics, neuroprotective agents, antiepileptics, agents...

A functional endocannabinoid system is present in several mammalian organs and tissues. Recently, endocannabinoids and their receptors have been reported in the skeleton. Osteoblasts, the bone forming cells, and osteoclasts, the bone resorbing cells, produce the endocannabinoids anandamide and 2-arachidonoylglycerol and express CB2 cannabinoid receptors. Although CB2 has been implicated in pathological processes in the central nervous system and peripheral tissues, the skeleton appears as the main system physiologically regulated by CB2. CB2-deficient mice show a markedly accelerated age-related bone loss and the CNR2 gene (encoding CB2) in women is associated with low bone mineral density. The activation of CB2 attenuates ovariectomy-induced bone loss...

The expression patterns of the cannabinoid receptor type 1 (CB1R) and the cannabinoid receptor type 2 (CB2R) are well documented in rodents and primates. In vervet monkeys, CB1R is present in the retinal neurons (photoreceptors, horizontal cells, bipolar cells, amacrine cells, and ganglion cells) and CB2R is exclusively found in the retinal glia (Muller cells). However, the role of these cannabinoid receptors in normal primate retinal function remains elusive. Using full-field electroretinography in adult vervet monkeys, we recorded changes in neural activity following the blockade of CB1R and CB2R by the intravitreal administration of their antagonists (AM251 and AM630, resp.) in photopic and scotopic...

Non-small cell lung cancer (NSCLC) is the leading cause of cancer deaths worldwide; however, only limited therapeutic treatments are available. Hence, we investigated the role of cannabinoid receptors, CB1 and CB2, as novel therapeutic targets against NSCLC. We observed expression of CB1 (24%) and CB2 (55%) in NSCLC patients. Furthermore, we have shown that the treatment of NSCLC cell lines (A549 and SW-1573) with CB1/CB2 and CB2-specific agonists Win55,212-2 and JWH-015, respectively, significantly attenuated random as well as growth factor-directed in vitro chemotaxis and chemoinvasion in these cells. We also observed significant reduction in focal adhesion complex, which plays an important role in migration,...

Abstract Chemotherapy-induced nausea is one of the most distressing symptoms reported by patients undergoing treatment, and even with the introduction of newer antiemetics such as ondansetron and aprepitant, nausea remains problematic in the clinic. Indeed, when acute nausea is not properly managed, the cues of the clinic can become associated with this distressing symptom resulting in anticipatory nausea for which no effective treatments are available. Clinical trials exploring the potential of exogenous or endogenous cannabinoids to reduce chemotherapy-induced nausea are sparse; therefore, we must rely on the data from pre-clinical rat models of nausea. In this review, we explore the human and pre-clinical animal...

Rich evidence has shown that cannabis products exert a broad gamut of effects on emotional regulation. The main psychoactive ingredient of hemp, Δ9 -tetrahydrocannabinol (THC), and its synthetic cannabinoid analogs have been reported to either attenuate or exacerbate anxiety and fear-related behaviors in humans and experimental animals. The heterogeneity of cannabisinduced psychological outcomes reflects a complex network of molecular interactions between the key neurobiological substrates of anxiety and fear and the endogenous cannabinoid system, mainly consisting of the arachidonic acid derivatives anandamide and 2-arachidonoylglycerol (2-AG) and two receptors, respectively termed CB1 and CB2. The high degree of interindividual variability in the responses to cannabis...