Tag Archives: therapeutic
Therapeutic effects of Delta9-THC and modafinil in a marmoset Parkinson model.
Abstract
“Current therapies for Parkinson’s disease (PD) like l-dopa and dopamine (DA) agonists have declined efficacy after long term use. Therefore, research towards supplementary or alternative medication is needed. The implementation in PD can be expedited by application of compounds already used in the clinic. In this study the therapeutic effects of the psychoactive compounds Delta(9)-tetrahydrocannabinol (Delta(9)-THC) and modafinil were tested in the 1-methyl-1,2,3,6-tetrahydropyridine (MPTP)-marmoset model for PD. The anti-parkinson effects of Delta(9)-THC (4 mg/kg) and modafinil (100 mg/kg) in parkinsonian marmosets were assessed with two behavioral rating scales covering parkinsonian symptoms and involuntary movements and two test systems assessing the locomotor activity and hand-eye coordination. Delta(9)-THC improved activity and hand-eye coordination, but induced compound-related side-effects. Modafinil improved activity and observed parkinsonian symptoms but not hand-eye coordination. It can be concluded that both compounds have therapeutic values and could supplement existing therapies for PD.”
The endocannabinoid system in Parkinson’s disease.
Abstract
“Parkinson’s disease (PD) is a chronic and progressive neurodegenerative disorder of largely unknown etiology caused by a pathological cascade resulting in the degeneration of midbrain dopaminergic neurons of the substantia nigra pars compacta (SNpc) projecting to the nucleus striatum, the main input station of the basal ganglia neuronal circuit. The components of the endocannabinoid (ECB) system are highly expressed at different levels in the basal ganglia neural circuit where they bidirectionally interact with dopaminergic, glutamatergic and GABAergic signaling systems. In particular, at synapses linking cortical and striatal neurons, endocannabinoids (ECBs) are known to critically modulate synaptic transmission and to mediate the induction of a particular form of synaptic plasticity, the long-term depression. The evidence that ECBs play a central role in regulating basal ganglia physiology and motor function and the profound modifications occurring in ECB signaling after dopamine depletion in both experimental models of PD and patients suffering from the disease, provide support for the development of pharmacological compounds targeting the ECB system as symptomatic and neuroprotective therapeutic strategies for PD.”
Therapeutic potential of cannabinoids in the treatment of neuroinflammation associated with Parkinson’s disease.
Abstract
“The cannabinoid system is represented by two principal receptor subtypes, termed CB1 and CB2, along with several endogenous ligands. In the central nervous system it is involved in several processes. CB1 receptors are mainly expressed by neurons and their activation is primarily implicated in psychotropic and motor effects of cannabinoids. CB2 receptors are expressed by glial cells and are thought to participate in regulation of neuroimmune reactions. This review aims to highlight several reported properties of cannabinoids that could be used to inhibit the adverse neuroinflammatory processes contributing to Parkinson’s disease and possibly other neurodegenerative disorders. These include anti-oxidant properties of phytocannabinoids and synthetic cannabinoids as well as hypothermic and antipyretic effects. However, cannabinoids may also trigger signaling cascades leading to impaired mitochondrial enzyme activity, reduced mitochondrial biogenesis, and increased oxidative stress, all of which could contribute to neurotoxicity. Therefore, further pharmacological studies are needed to allow rational design of new cannabinoid-based drugs lacking detrimental in vivo effects.”
Cannabinoid CB1 antagonists possess antiparkinsonian efficacy only in rats with very severe nigral lesion in experimental parkinsonism.
Abstract
“We have observed that systemic administration of cannabinoid CB1 antagonists exerts antiparkinsonian effects in rats with very severe nigral lesion (>95% cell loss), but not in rats with less severe lesion (85-95% cell loss). Local injections into denervated striatum and corresponding globus pallidus reduced parkinsonian asymmetry. Infusions into lesioned substantia nigra enhanced motor asymmetries, but this effect was absent after very severe nigral lesion. At the striatal level, CB1 antagonists act enhancing dopamine D1 receptor function and reducing D2 receptor function. Striatal dopaminergic denervation did not affect cannabinoid CB1 receptor coupling to G proteins. These results suggest that (i) systemic administration of CB1 antagonists in rats with severe nigral degeneration is ineffective because striatopallidal-mediated motor effects are antagonized by nigra-mediated activity, and (ii) CB1 antagonists exert antiparkinsonian effects after very severe nigral degeneration because nigra-mediated inhibition disappears. CB1 receptor antagonists that lack psychoactive effects might be of therapeutic value in the control of very advanced stage of Parkinson’s disease in humans.”
CB1 cannabinoid receptor signalling in Parkinson’s disease.
Abstract
“Signalling at CB(1) cannabinoid receptors plays a key role in the control of movement in health and disease. In recent years, an increased understanding of the physiological role of transmission at CB(1) receptors throughout the basal ganglia circuitry has led to the identification of novel therapeutic approaches to both the symptoms of Parkinson’s disease and the side effects of current anti-parkinsonian therapies, especially L(3,4) dihydroxyphenylalamine (levodopa)-induced dyskinesia. Thus, because activation of basal ganglia CB(1) receptors can modulate neurotransmission and contribute to synaptic plasticity in a manner similar to that described in other brain regions, it also appears that endocannabinoids might modulate cell-cell signalling via effects on neurotransmitter re-uptake and postsynaptic actions mediating cross talk between multiple receptor types. Recent studies in animal models and in the clinic suggest that CB(1) receptor antagonists could prove useful in the treatment of parkinsonian symptoms and levodopa-induced dyskinesia, whereas CB(1) receptor agonists could have value in reducing levodopa-induced dyskinesia.”
Depression in Parkinson’s disease is related to a genetic polymorphism of the cannabinoid receptor gene (CNR1).
Abstract
“Depression is a common symptom in Parkinson’s disease (PD) and it is present in up to 40% of the patients. The cause of depression in PD is thought to be related to disturbance of monoamine neurotransmission. The endogenous cannabinoid system mediates different brain processes that play a role in the control of behaviour and emotions. Cannabinoid function may be altered in neuropsychiatry diseases, directly or through interactions with monoamine, GABA and glutamate systems. For this reason, we have investigated whether there is a genetic risk factor for depression in PD linked to the polymorphisms of CB1 receptor gene. Depression was more frequent in patients with PD than in controls with osteoarthritis. The presence of depression did not correlate with the stage of the disease but it was more frequent in patients with pure akinetic syndrome than in those with tremoric or mixed type PD. The CB1 receptor gene polymorphism (AAT)n is considered to modify the transcription of the gene and, therefore, it may have functional relevance. We analysed the length of the polymorphic triplet (AAT)n of the gene that encodes CB1 (CNR1) receptor in 89 subjects (48 PD patients and 41 controls). In patients with PD, the presence of two long alleles, with more than 16 repeated AAT trinucleotides in the CNR1 gene, was associated with a reduced prevalence of depression (Fisher’s exact test: P=0.003). This association did not reach significant differences in the control group, but the number of control individuals with depression was too small to allow for statistical analysis. Since the alleles with long expansions may have functional impact in cannabinoid neurotransmission, our data suggest that the pharmacological manipulation of cannabinoid neurotransmission could open a new therapeutic approach for the treatment of depression in PD and possibly in other conditions.”
Smoked cannabis proven effective in treating neuropathic pain.
“Smoked cannabis eased pain induced in healthy volunteers, according to a study by researchers at the University of California, San Diego (UCSD) Center for Medical Cannabis Research (CMCR.) However, the researchers found that less may be more.”
“The results, showing a medium-dose (4% THC by weight) of cannabis to be an effective analgesic, converged with results from the CMCR’s first published study, a paper by UCSF researcher Donald Abrams, M.D. published in the journal Neurology in February 2007. In that randomized placebo-controlled trial, patients smoking the same dose of cannabis experienced a 34% reduction in HIV-associated sensory neuropathy pain—twice the rate experienced by patients receiving a placebo.”
““This study helps to build a case that cannabis does have therapeutic value at a medium-dose level,” said Grant. “It also suggests that higher doses aren’t necessarily better in certain situations – something also observed with other medications, such as antidepressants.””
Read more: http://phys.org/news112456382.html
“Smoked Cannabis Proven Effective In Treating Neuropathic Pain” https://www.sciencedaily.com/releases/2007/10/071024141745.htm
“Smoked cannabis proven effective in treating neuropathic pain” https://medicalxpress.com/news/2007-10-cannabis-proven-effective-neuropathic-pain.html
“Smoked Cannabis Proven Effective in Treating Neuropathic Pain” https://health.ucsd.edu/news/2007/pages/10-24-medical-cannabis.aspx
Role of cannabinoids in the management of neuropathic pain.
Abstract
“The treatment of pain, particularly neuropathic pain, is one of the therapeutic applications of cannabis and cannabinoids that is currently under investigation and that stimulates interest among clinicians and basic researchers. Animal pain models, including models of acute, antinociceptive, inflammatory and neuropathic pain, have demonstrated the antinociceptive efficacy of cannabinoids without causing serious alterations in animal behaviour. These data, together with the historic and current empiric use of cannabinoids, support the interest in the analysis of their effectiveness in treating neuropathic pain. The evaluation of controlled trials that focus on the effect of cannabinoids on neuropathic pain reveals that this class of drugs is able to significantly reduce pain perception. Nevertheless, this effect is generally weak and clinical relevance remains under evaluation. Moreover, there is a lack of controlled trials and, in particular, comparisons with other drugs generally used in the treatment of neuropathic pain. Despite the fact that further research is required to achieve a definitive assessment, current data obtained from basic research and from analysis of the available controlled trials indicate that cannabinoids can be accepted as a useful option in the treatment of neuropathic pain.”
Antihyperalgesic effect of a Cannabis sativa extract in a rat model of neuropathic pain: mechanisms involved.
Abstract
“This study aimed to give a rationale for the employment of phytocannabinoid formulations to treat neuropathic pain. It was found that a controlled cannabis extract, containing multiple cannabinoids, in a defined ratio, and other non-cannabinoid fractions (terpenes and flavonoids) provided better antinociceptive efficacy than the single cannabinoid given alone, when tested in a rat model of neuropathic pain. The results also demonstrated that such an antihyperalgesic effect did not involve the cannabinoid CB1 and CB2 receptors, whereas it was mediated by vanilloid receptors TRPV1. The non-psychoactive compound, cannabidiol, is the only component present at a high level in the extract able to bind to this receptor: thus cannabidiol was the drug responsible for the antinociceptive behaviour observed. In addition, the results showed that after chronic oral treatment with cannabis extract the hepatic total content of cytochrome P450 was strongly inhibited as well as the intestinal P-glycoprotein activity. It is suggested that the inhibition of hepatic metabolism determined an increased bioavailability of cannabidiol resulting in a greater effect. However, in the light of the well known antioxidant and antiinflammatory properties of terpenes and flavonoids which could significantly contribute to the therapeutic effects, it cannot be excluded that the synergism observed might be achieved also in the absence of the cytochrome P450 inhibition.”