“Accumulating evidence suggests that cannabinoid ligands play delicate roles in cell survival and apoptosis decisions, and that cannabinoid CB1 receptors (CB1R) modulate dopaminergic function. However, the role of CB1R in methamphetamine (MA)-induced dopaminergic neurotoxicity in vivo remains elusive. Multiple high doses of MA increased phospho-ERK and CB1R mRNA expressions in the striatum of CB1R (+/+) mice. These increases were attenuated by CB1R antagonists (i.e., AM251 and rimonabant), an ERK inhibitor (U0126), or dopamine D2R antagonist (sulpiride). CB1R agonist-induced toxic effects were significantly attenuated by CB1R knockout, CB1R antagonists or PKCδ knockout. Therefore, our results suggest that interaction between D2R, ERK and CB1R is critical for MA-induced dopaminergic neurotoxicity and that PKCδ mediates dopaminergic damage induced by high-doses of CB1R agonist.” https://www.ncbi.nlm.nih.gov/pubmed/28363605]]>
Monthly Archives: April 2017
Comparative antinociceptive effect of arachidonylcyclopropylamide, a cannabinoid 1 receptor agonist & lignocaine, a local anaesthetic agent, following direct intrawound administration in rats.
“Treatment of inflammatory pain with opioids is accompanied by unpleasant and, at times, life-threatening side effects.
Cannabis produces antinociception as well as psychotropic effects. It was hypothesized that peripheral cannabinoid receptors outside the central nervous system could be selectively activated for relief of pain.
This study was undertaken to measure the antinociceptive effect of type 1 cannabinoid receptor (CB1r) agonist arachidonylcyclopropylamide (ACPA) in a rat model of inflammatory pain after intrawound administration and the effects were compared with lignocaine.
Lignocaine attenuated evoked pain behaviour whereas ACPA decreased guarding score. This difference was likely due to blockade of sodium ion channels and the activation of peripheral CB1r, respectively. Central side effects were absent after ACPA treatment. Further studies need to be done to assess the effect of ACPA treatment in clinical conditions.”
Comparative antinociceptive effect of arachidonylcyclopropylamide, a cannabinoid 1 receptor agonist & lignocaine, a local anaesthetic agent, following direct intrawound administration in rats.
“Treatment of inflammatory pain with opioids is accompanied by unpleasant and, at times, life-threatening side effects.
Cannabis produces antinociception as well as psychotropic effects. It was hypothesized that peripheral cannabinoid receptors outside the central nervous system could be selectively activated for relief of pain.
This study was undertaken to measure the antinociceptive effect of type 1 cannabinoid receptor (CB1r) agonist arachidonylcyclopropylamide (ACPA) in a rat model of inflammatory pain after intrawound administration and the effects were compared with lignocaine.
Lignocaine attenuated evoked pain behaviour whereas ACPA decreased guarding score. This difference was likely due to blockade of sodium ion channels and the activation of peripheral CB1r, respectively. Central side effects were absent after ACPA treatment. Further studies need to be done to assess the effect of ACPA treatment in clinical conditions.”
https://www.ncbi.nlm.nih.gov/pubmed/28361827
Activation of CB1 receptors by 2-arachidonoylglycerol attenuates vasoconstriction induced by U46619 and angiotensin II in human and rat pulmonary arteries.
“Recent evidence suggests that endocannabinoids acting via cannabinoid CB1 receptors may modulate vascular responses of various vasoconstrictors in the rodent systemic vasculature. The aim of the study was to investigate whether endocannabinoids modulate the contractile responses evoked by a thromboxane A2 analog (U46619), angiotensin II (Ang II), serotonin (5-HT) and phenylephrine which stimulate distinct Gq/11-protein coupled receptors (TP, AT1, 5-HT2 and α1-adrenergic) in isolated endothelium-intact human (hPAs) and rat pulmonary arteries (rPAs). The present study shows the protective interaction between the endocannabinoid system and vasoconstriction to U46619 and Ang II in the human and rat pulmonary circulation. U46619 and Ang II may stimulate rapid endothelial release of endocannabinoids (mainly 2-arachidonoylglycerol), leading to CB1 receptor-dependent and/or -independent vasorelaxation, which in the negative feedback mechanism reduces later agonists-induced vasoconstriction.” https://www.ncbi.nlm.nih.gov/pubmed/28356298 http://ajpregu.physiology.org/content/early/2017/03/27/ajpregu.00324.2016]]>
Regulation of Cell Surface CB2 Receptor during Human B Cell Activation and Differentiation.
“Cannabinoid receptor type 2 (CB2) is the primary receptor pathway mediating the immunologic consequences of cannabinoids.
We recently reported that human peripheral blood B cells express CB2 on both the extracellular membrane and at intracellular sites, where-as monocytes and T cells only express intracellular CB2. To better understand the pattern of CB2 expression by human B cells, we examined CD20+ B cells from three tissue sources.
Both surface and intracellular expression were present and uniform in cord blood B cells, where all cells exhibited a naïve mature phenotype (IgD+/CD38Dim). While naïve mature and quiescent memory B cells (IgD–/CD38–) from tonsils and peripheral blood exhibited a similar pattern, tonsillar activated B cells (IgD–/CD38+) expressed little to no surface CB2.
We hypothesized that regulation of the surface CB2 receptor may occur during B cell activation. Consistent with this, a B cell lymphoma cell line known to exhibit an activated phenotype (SUDHL-4) was found to lack cell surface CB2 but express intracellular CB2.
Furthermore, in vitro activation of human cord blood resulted in a down-regulation of surface CB2 on those B cells acquiring the activated phenotype but not on those retaining IgD expression. Using a CB2 expressing cell line (293 T/CB2-GFP), confocal microscopy confirmed the presence of both cell surface expression and multifocal intracellular expression, the latter of which co-localized with endoplasmic reticulum but not with mitochondria, lysosomes, or nucleus.
Our findings suggest a dynamic multi-compartment expression pattern for CB2 in B cells that is specifically modulated during the course of B cell activation.”
