“The main pathological feature of Parkinson’s disease (PD) is the loss of dopaminergic neurons in the substantia nigra. In this study, we investigated the role of cannabinoid receptor 2 (CB2R) agonist AM1241 on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in a mouse model of PD. Upon treatment with AM1241, the decreased CB2R level in the PD mouse brain was reversed and the behavior score markedly elevated, accompanied with a dose-dependent increase of dopamine and serotonin. In addition, western blot assay and immunostaining results suggested that AM1241 significantly activated PI3K/Akt/MEK phosphorylation and increased the expression of Parkin and PINK1, both in the substantia nigra and hippocampus. The mRNA expression analysis further demonstrated that AM1241 increased expression of the CB2R and activated Parkin/PINK1 signaling pathways. Furthermore, the increased number of TH-positive cells in the substantia nigra indicated that AM1241 regenerated DA neurons in PD mice, and could therefore be a potential candidate for PD treatment. The clear co-localization of CB2R and DA neurons suggested that AM1241 targeted CB2R, thus also identifying a novel target for PD treatment. In conclusion, the selective CB2 agonist AM1241 has a significant therapeutic effect on PD mice and resulted in regeneration of DA neurons following MPTP-induced neurotoxicity. The possible mechanisms underlying the neurogenesis effect of AM1241 might be the induction of CB2R expression and an increase in phosphorylation of the PI3K/AKT signaling pathway.”
“In the era of combined antiretroviral therapy (cART), human immunodeficiency virus type 1 (HIV-1) is considered a chronic disease that specifically targets the brain and causes HIV-1-associated neurocognitive disorders (HAND). Endocannabinoids (eCBs) elicit neuroprotective and anti-inflammatory actions in several central nervous system (CNS) disease models, but their effects in HAND remain unknown. HIV-1 does not infect neurons, but produces viral toxins, such as transactivator of transcription (Tat), that disrupt neuronal calcium equilibrium and give rise to synaptodendritic injuries and cell death, the former being highly correlated with HAND. Consequently, we tested whether the eCBs N-arachidonoyl ethanolamine (anandamide/AEA) and 2-arachidonoyl-glycerol (2-AG) offer neuroprotective actions in a neuronal culture model. Specifically, we examined the neuroprotective actions of these eCBs on Tat excitotoxicity in primary cultures of prefrontal cortex neurons (PFC), and whether cannabinoid receptors mediate this neuroprotection. Tat-induced excitotoxicity was reflected by increased intracellular calcium levels, synaptodendritic damage, neuronal excitability, and neuronal death. Further, upregulation of cannabinoid 1 receptor (CB1R) protein levels was noted in the presence of HIV-1 Tat. The direct application of AEA and 2-AG reduced excitotoxic levels of intracellular calcium and promoted neuronal survival following Tat exposure, which was prevented by the CB1R antagonist rimonabant, but not by the CB2R antagonist AM630. Overall, our findings indicate that eCBs protect PFC neurons from Tat excitotoxicity in vitro via a CB1R-related mechanism. Thus, the eCB system possesses promising targets for treatment of neurodegenerative disorders associated with HIV-1 infection.”
“The endocannabinoid system is thought to modulate nociceptive signaling making it a potential therapeutic target for treating pain.
However, there is evidence that endocannabinoids have both pro- and anti-nociceptive effects. In previous studies using Hirudo verbana (the medicinal leech), endocannabinoids were found to depress nociceptive synapses, but enhance non-nociceptive synapses. Here we examined whether endocannabinoids have similar bidirectional effects on behavioral responses to nociceptive vs. non-nociceptive stimuli in vivo.
These results provide evidence that endocannabinoids can have opposing effects on nociceptive vs. non-nociceptive pathways and suggest that cannabinoid-based therapies may be more appropriate for treating pain disorders in which hyperalgesia and not allodynia is the primary symptom.”
“Neuroinflammation plays a major role in postoperative cognitive dysfunction (POCD).
Accumulated evidence indicates that cannabinoid receptor type 2 (CB2R) can mediate anti-inflammatory and immunomodulatory effects in part by controlling microglial activity.
These findings indicate that CB2R may modulate the neuroinflammatory and cognitive impairment in a mouse model of orthopedic surgery, and the activation of CB2R may effectively ameliorate the hippocampal-dependent memory loss of mice in the early postoperative stage.”
“This study investigated whether intramuscular injection of delta-9-tetrahydrocannabinol (THC), by acting on peripheral cannabinoid (CB) receptors, could decrease nerve growth factor (NGF)-induced sensitization in female rat masseter muscle; a model which mimics the symptoms of myofascial temporomandibular disorders.
It was found that CB1 and CB2 receptors are expressed by trigeminal ganglion neurons that innervate the masseter muscle and also on their peripheral endings.
These results suggest that reduced inhibitory input from the peripheral cannabinoid system may contribute to NGF-induced local myofascial sensitization of mechanoreceptors. Peripheral application of THC may counter this effect by activating the CB1 receptors on masseter muscle mechanoreceptors to provide analgesic relief without central side effects.
Our results suggest THC could reduce masticatory muscle pain through activating peripheral CB1 receptors. Peripheral application of cannabinoids could be a novel approach to provide analgesic relief without central side effects.”
“The beta amyloid (Aβ) and other aggregating proteins in the brain increase with age and are frequently found within neurons. The mechanistic relationship between intracellular amyloid, aging and neurodegeneration is not, however, well understood.
We use a proteotoxicity model based upon the inducible expression of Aβ in a human central nervous system nerve cell line to characterize a distinct form of nerve cell death caused by intracellular Aβ. It is shown that intracellular Aβ initiates a toxic inflammatory response leading to the cell’s demise. Aβ induces the expression of multiple proinflammatory genes and an increase in both arachidonic acid and eicosanoids, including prostaglandins that are neuroprotective and leukotrienes that potentiate death.
Cannabinoids such as tetrahydrocannabinol stimulate the removal of intraneuronal Aβ, block the inflammatory response, and are protective.
Altogether these data show that there is a complex and likely autocatalytic inflammatory response within nerve cells caused by the accumulation of intracellular Aβ, and that this early form of proteotoxicity can be blocked by the activation of cannabinoid receptors.”
“The essential role of GAPDH/Siah1 signaling pathway in the pathogenesis of various injurious conditions such as traumatic spinal cord injury (SCI) has been gradually recognized. However, the drugs targeting this signaling pathway are still lacking.
The endocannabinoid system, including its receptors (CB1 and CB2), act as neuroprotective and immunomodulatory modulators in SCI. WIN55212-2, an agonist for CB1 and CB2 receptors, has been demonstrated with anti-inflammatory and anti-apoptotic effects in multiple neurological diseases. Therefore, the present study aimed to investigate whether WIN55212-2 could promote functional recovery after traumatic SCI via inhibition of the GAPDH/Siah1 signaling.
In conclusion, our study indicates that, WIN55212-2 improves the functional recovery after SCI via inhibition of GAPDH/Siah1 cascades in a CB2 receptor dependent manner, indicative of its therapeutic potential for traumatic SCI or other traumatic conditions.”
“Cannabinoid type 2 (CB2) receptors are distributed in central and peripheral tissues, including immunocytes and the gastrointestinal (GI) tract, suggesting that CB2 receptor agonists represent potential therapeutics in GI inflammatory states.
In this study, we investigated the effect of highly selective CB2 agonist, A836339, on the development of gastric lesions.
Activation of CB2 receptors exhibited gastroprotective effect through enhancement of anti-oxidative pathways in the stomach. Activation of CB2 receptors may thus become a novel therapeutic approach in the treatment of GU.”
“The bed nucleus of the stria terminalis (BNST) is a region of the extended amygdala that is implicated in addiction, anxiety, and stress related behaviors. This region has been identified in mediating the aversive state of naloxone-precipitated morphine withdrawal (MWD) and cannabinoid Type I (CB1) receptors have been found to modulate neurotransmission within this region.
Previous findings suggest that the CB1 antagonist/inverse agonist, AM251, administered systemically or by infusion into the central nucleus of the amygdala (CeA) prevented the aversive affective properties of MWD as measured by conditioned place aversion learning.
The current findings emphasize an important role for the BNST in opioid withdrawal and suggest that the ameliorative effects of systemically administered CB1 antagonists are mediated, in part, by their actions within this region.”
“Multiple sclerosis (MS) is a chronic demyelinating central nervous system (CNS) disease that involve oligodendrocyte loss and failure to remyelinate damaged brain areas causing a progressive neurological disability.
Studies in MS mouse model suggest that cannabinoids ameliorate symptoms as spasticity, tremor and pain reducing inflammation via cannabinoid-mediated system.
The aim of our study is to investigate the changes in cannabinoid type 1 (CNR1) and 2 (CNR2) receptors mRNA expression levels and promoter methylation in peripheral blood mononuclear cells (PBMCs) of MS secondary progressive (MSS-SP) patients treated with Sativex®.
These results suggest that the different expression of cannabinoid receptors by Sativex® treatment in leukocytes might be regulated through a molecular mechanism that involve interferon modulation.”