BACKGROUND AND PURPOSETwo non-psychoactive cannabinoids, cannabidiol (CBD) and cannabichromene (CBC), are known to modulate in vitro the activity of proteins involved in nociceptive mechanisms, including transient receptor potential (TRP) channels of vanilloid type-1 (TRPV1) and of ankyrin type-1 (TRPA1), the equilibrative nucleoside transporter and proteins facilitating endocannabinoid inactivation. Here we have tested these two cannabinoids on the activity of the descending pathway of antinociception.
EXPERIMENTAL APPROACHElectrical activity of ON and OFF neurons of the rostral ventromedial medulla in anaesthetized rats was recorded extracellularly and tail flick latencies to thermal stimuli were measured. CBD or CBC along with various antagonists were injected into the ventrolateral periaqueductal grey.
KEY RESULTSCannabidiol and CBC dose-dependently reduced the ongoing activity of ON and OFF neurons in anaesthetized rats, whilst inducing antinociceptive responses in the tail flick-test. These effects were maximal with 3 nmol CBD and 6 nmol CBC, and were antagonized by selective antagonists of cannabinoid CB1 adenosine A1 and TRPA1, but not of TRPV1, receptors. Both CBC and CBD also significantly elevated endocannabinoid levels in the ventrolateral periaqueductal grey. A specific agonist at TRPA1 channels and a synthetic inhibitor of endocannabinoid cellular reuptake exerted effects similar to those of CBC and CBD.
CONCLUSIONS AND IMPLICATIONSCBD and CBC stimulated descending pathways of antinociception and caused analgesia by interacting with several target proteins involved in nociceptive control. These compounds might represent useful therapeutic agents with multiple mechanisms of action.
BJP
SummaryBackground Immunotherapy is a recognized treatment for allergic respiratory diseases. Objective To study the usefulness of immunotherapy in combination with optimal pharmacological therapy. Methods Thirty-eight children (8-14 years) suffering from seasonal asthma7rhinoconjunctivitis due to Parietaria poorly controlled by anti-allergic drugs treatment were selected. After randomization according to a double-blind placebo-controlled design they received active sublingual immunotherapy (15 children) or placebo (15 children) for 13 months combined with inhaled fluticasone twice a day during the pollen season. Eight children were taken as control, whereas all patients were instructed to take symptomatic drugs on need. Early and late skin response to the allergen were assessed in all patients before and after treatment. Drug and symptom scores, as well as visual analogue scores (VASs) and Parietaria pollen counts were assessed during the pollen season. Results Groups were well balanced for age, gender, early and late skin response before treatment. Four children dropped out, in one case in relationship with active sublingual immunotherapy (SLIT) administration. Chest and nose symptoms, as well as drug scores and VASs were significantly better in both the active or placebo SLIT1fluticasone (S1F) as compared to the control group (P between o0.001 and 0.043). Eye symptoms were significantly better in the active S1F group as compared to
The current study has investigated the involvement of periaqueductal gray (PAG) metabotropic glutamate subtype 7 and 8 receptors (mGluR(7) and mGluR(8)) in modulating rostral ventromedial medulla (RVM) ongoing and tail flick-related on and off cell activities. Our study has also investigated the role of PAG mGluR(7) on thermoceptive threshold and PAG glutamate and GABA release. Intra-ventrolateral PAG (S)-3,4-dicarboxyphenylglycine [(S)-3,4-DCPG (2 and 4 nmol/rat)] or N,N(I)-dibenzhydrylethane-1,2-diamin dihydrochloride (AMN082, (1 and 2 nmol/rat), selective mGluR(8) and mGluR(7) agonists, respectively, caused opposite effects on the ongoing RVM on and off cell activities. Tail flick latency was increased or decreased by (S)-3,4-DCPG or AMN082 (2 nmol/rat), respectively. (S)-3,4-DCPG reduced the pause and delayed the onset of the off cell pause. Conversely, AMN082 increased the pause and shortened the onset of off cell pause. (S)-3,4-DCPG or AMN082 did not change the tail flick-induced onset of on-cell peak firing. The tail flick latency and its related electrophysiological effects induced by (S)-3,4-DCPG or AMN082 were prevented by (RS)-alpha-methylserine-o-phosphate (100 nmol/rat), a group III mGluR antagonist. Intra-ventrolateral PAG perfusion with AMN082 (10 and 25 microM), decreased thermoceptive thresholds and glutamate extracellular levels. A decrease in GABA release was also observed. These results show that stimulation of PAG mGluR(8) or mGluR(7) could either relieve or worsen pain perception. The opposite effects on pain behavior correlate with the opposite roles played by mGluR(7) and mGluR(8) on glutamate and GABA release and the ongoing and tail flick-related activities of the RVM on and off cells.
The presence of CD in children with CU was significantly more frequent than in controls. GFD resulted in urticaria remission. CD may be regarded in such subjects as a cause of CU.
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