CNS & Neurological Disorders - Drug Targets (Formerly Current Drug Targets - CNS & Neurological Disorders) - Volume 16, Issue 5, 2017

Background & Objective: Medical cannabis is increasingly used as a treatment or adjunct treatment with different levels of efficacy in several neurological disorders or related symptoms (such as multiple sclerosis, autism, Parkinson and Alzheimer disease, Tourette128;™s syndrome, Huntington's disease, neuropathic pain, epilepsy, headache), as well as in other medical 'conditions (e.g. nausea and vomiting, glaucoma, appetite stimulation, cancer, inflammatory conditions, asthma). Nevertheless, a number of neurological adverse effects from use of medical cannabis on the short- and on the longterm have been reported, in addition to other adverse health events. Conclusion: It has been noticed that the use of medical cannabis can lead to a paradoxical effects depending on the amount of delta-9-tetrahydrocannabinol (THC) -like cannabinoids the preparation contain. Accordingly, some neurological disorders or symptoms (e.g. multiple sclerosis, seizures, epilepsy, headache) may be caused or exacerbated by the same treatment supposed to cure them. The current review presents an update of the neurological adverse effects resulting from the use of cannabis for medical purposes, highlighting the need to weigh the benefits and risks, when using cannabinoidbased treatments.

Background & Objective: Delta (9)-tetrahydrocannabinol (THC) is the main psychoactive compound in cannabis and is frequently identified in blood samples from apprehended drivers suspected for driving under the influence of drugs. Changing social norms towards cannabis and higher acceptability towards the drug emphasize the need for in-depth understanding of the acute neurocognitive and psychomotor effects caused by cannabis and how these effects are correlated to driving skills and performance. Method: In this review, PubMed, Cochrane Central, Scopus, Web of Science, Science Direct, EMBASE and Google Scholar databases were used to identify and select publications up to January 2017 dealing with acute and chronic neurocognitive effects induced by cannabis and ability to drive. Thirty-six publications were selected for this review. The studies conducted were experimental, using simulators or on-road studies and brain imaging (structural and functional) to better understand the acute and chronic effects on cognitive functions comprised in the short and long-term fitness to drive after cannabis consumption. Conclusion: In a case-crossover self-report study a significant odds ratio increase was found for driving-related injury after combined exposure to cannabis and alcohol compared to cannabis alone (OR of 10.9 and 5.8 respectively). Both, experimental and epidemiological studies have revealed that THC affects negatively both, psychomotor skills and cognitive functions. Studies of the acute effects of cannabis on driving have shown that drivers under the influence of this substance are impaired. Indeed, driving under the influence of cannabis doubles or triples the risk of a crash. Specifically, cannabis use impairs critical-tracking tasks, increases lane weaving, decreases reaction time, and divided attention.

Background: Cannabidiol (CBD) is among the major secondary metabolites of Cannabis devoid of the delta-9-tetra-hydrocannabinol psychoactive effects. It is a resorcinol-based compound with a broad spectrum of potential therapeutic properties, including neuroprotective effects in numerous pathological conditions. CBD neuroprotection is due to its antioxidant and antiinflammatory activities and the modulation of a large number of brain biological targets (receptors, channels) involved in the development and maintenance of neurodegenerative diseases. Objective: The aim of the present review was to describe the state of art about the pre-clinical research, the potential use and, when existing, the clinical evidence related to CBD in the neurological field. Method: Collection of all the pre-clinical and clinical findings carried out investigating the effects of CBD alone, not in combination with other substances, in the neurological arena with the exclusion of studies on neuropsychiatric disorders. Results: Laboratory and clinical studies on the potential role of CBD in Parkinson's disease (PD), Alzheimer's disease (AD), multiple sclerosis (MS), Huntington's disease (HD), amyotrophic lateral sclerosis ALS), cerebral ischemia, were examined. Conclusion: Pre-clinical evidence largely shows that CBD can produce beneficial effects in AD, PD and MS patients, but its employment for these disorders needs further confirmation from well designed clinical studies. CBD pre-clinical demonstration of antiepileptic activity is supported by recent clinical studies in human epileptic subjects resistant to standard antiepileptic drugs showing its potential use in children and young adults affected by refractory epilepsy. Evidence for use of CBD in PD is still not supported by sufficient data whereas only a few studies including a small number of patients are available.

Background & Objective: Cannabis is the most widely used illicit drug. The two most important natural cannabinoids are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). The THC content of cannabis has been increasing during the last years and recently appeared in the market as a series of synthetic cannabinoids with potent agonist activity. Recreational users frequently combine cannabis with other drugs of abuse as alcohol, amphetamines and derivatives, nicotine and cocaine. In addition, these subjects can be taking medicines for acute and chronic medical conditions. The increasing use of medicinal cannabis for chronic pain and neurological and psychiatric disorders can produce potential interactions with medications used for the symptomatic treatment of these or other diseases. Conclusion: THC and CBD are metabolized mainly in the liver by cytochrome P-450 isoenzymes (mainly CYP2Cs and CYP3A4). In vitro studies indicate that THC and CBD both inhibit CYP1A1, 1A2 and 1B1 enzymes, and recent studies have indicated that CBD is also a potent inhibitor of CYP2C19 and CYP3A4. Both cannabinoids may interact with other medications metabolized by the same pathway or by inducers/inhibitors of the isoenzymes. Cannabis produces sedation, impairs psychomotor performance, and increases blood pressure and heart rate. Pharmacodynamic interactions with other sedatives can potentiate the central effects but can be decreased by psychostimulants. This review focuses on the interactions between cannabinoids and alcohol, other drugs of abuse, and prescription medicines.

Background: Synthetic Cannabinoids (SC) are the widest and most diffused class of Novel Psychoactive Substances. The short- and long- term health risks associated with the consumption of SC are often unknown to both users and health professionals. This review aims to provide a synthesis of the most recent and relevant insights on the pharmacology, clinical and psychopathological aspects of SC. Method: A structured search of two bibliographic databases (PubMed and Scopus) was undertaken according to inclusion/exclusion criteria. The following terms “synthetic cannabinoid*”, “synthetic cannabimimetic*”, “synthetic cannabis”, “synthetic marijuana” and “Spice AND cannabinoid*” were used as search strings. Results: 162 relevant results, mainly published in the past two years were revealed. Most results emerged for the keyword “synthetic cannabinoid*”, followed by the combination “Spice* AND “cannabinoid*”. Most papers were epidemiological, forensic, toxicologic, or analytical. The results of studies were systematized according their contribution to the comprehension of pharmacological, clinical and psychopathological effects of SC. Fifteen SC-related fatality cases were reviewed according to their histories, pathology and toxicology findings. Conclusion: The findings of this review confirm the importance of prompt and reliable information available for health professionals More specific analytic techniques and designed preventive strategies are required to face unprecedented SC challenge.

Background: Since ancient times, the use of cannabis as a medicine is well documented due to its potential therapeutic activity while subsequently its use as drug of abuse spread increasingly. Objective: The present review sought to give an insight in the history of medical and recreational use of cannabis in India. Conclusion: Indian use of cannabis dates back to Vedic time, mostly for the ritualistic and religious purposes, as documented in the ancient literature. It was India that introduced the medical use of cannabis to neighboring countries. Nevertheless, in the same India, medical use did not propagate due to religious and social stigma related to the plant itself. The pharmacoactive constituents of cannabis and their therapeutic values in Ayurvetic medicine have been here described together with the adverse effects they can cause with special reference to neurological ones, including withdrawal symptoms. Finally, how cannabis made its route to the Indian society has also been discussed.

Background: Substance use, including cannabis, has been documented amongst women both in the pre-conception period and during pregnancy, particularly during the 1st trimester, which is clearly the most critical period in the organogenesis. The recent emergence on the drug market of synthetic cannabimimetics/SC (‘spice’) may represent a new challenge for clinicians. Objective: A literature overview on the teratogenicity profile of both cannabis and synthetic cannabimimetics was here carried out. Method: The PubMed database was searched in order to collect all relevant cases and data regarding the possible evidence of teratogenicity issues associated with cannabis and SC intake. Results: The use of cannabis in pregnant women has been associated with a plethora of both obstetrical/gestational complications and neurobehavioral/neurological effects on newborns. Conversely, only few and conflicting data are related to SC misuse issues. Conclusion: Although cannabis use may be considered a risk factor for the occurrence of pregnancyrelated morbidity issues, many studies relied on self-reports and showed inconsistent results when controlling for potential confounders, including tobacco use. Given the role of the endocannabinoid system in both pregnancy and delivery, SC potency at interacting with the endocannabinoid system may be a reason of concern. Clinicians should carefully assess each woman planning a pregnancy, or who is pregnant already, and who is at risk of persisting in her current cannabis and/or SC intake. A nonjudgmental approach, aiming at collecting both a history of drug/alcohol use and at providing information regarding the risks associated with cannabis/SC intake during pregnancy is here advised.

Background: Concurrent use of cannabis and alcohol is frequent. According different studies, the prevalence is among 20-34% depending on different samples studied. Objective: In contrast with the wide evidence available about neuropsychiatric effects associated to the use of cannabis or alcohol separately, there are few studies of the neuropsychiatric effects of their combination. Our aim was to review the literature regarding this topic. Conclusion: We performed a search in MEDLINE and from 114 potentially eligible studies, 27 were selected. Most of them studied the relation between cannabis and alcohol, and with them combined to other substances of abuse, but only a few considered their concurrent effect among mental disorders (ADHD, bipolar disorder) and neuropsychological performance. More research in the neuropsychiatric effects of the concomitant use of cannabis and alcohol is needed.

Background: Cannabis is the illicit drug with both the largest current levels of consumption and the highest reported lifetime prevalence levels in the world. Across different countries, the prevalence of cannabis use varies according to the individual income, with the highest use being reported in North America, Australia and Europe. Despite its ‘soft drug’ reputation, cannabis misuse may be associated with several acute and chronic adverse effects. Objective: The present article aims at reviewing several papers on epidemiological, neurobiological and psychopathological aspects of the use of cannabis. The PubMed database was here examined in order to collect and discuss a range of identified papers. Discussion: Cannabis intake usually starts during late adolescence/early adulthood (15-24 years) and drastically decreases in adulthood with the acquisition of working, familiar and social responsibilities. Clinical evidence supports the current socio-epidemiological alarm concerning the increased consumption among youngsters and the risks related to the onset of psychotic disorders. The mechanism of action of cannabis presents some analogies with other abused drugs, e.g. opiates. Furthermore, it has been well demonstrated that cannabis intake in adolescence may facilitate the transition to the use and/or abuse of other psychotropic drugs, hence properly being considered a ‘gateway drug’. Some considerations on synthetic cannabimimetics are provided here as well. Conclusion: In conclusion, the highest prevalence of cannabis use and the social perception of a relatively low associated risk are in contrast with current knowledge based on biological and clinical evidence. Indeed, there are concerns relating to cannabis intake association with detrimental effects on both cognitive impairment and mental health.

Background: Metabotropic glutamate could contribute to the development of neuropathic pain-related behaviors. Previously, we have confirmed that the glutamic acid and dizocilpine maleate in the hippocampal CA3 region are involved in the modulation of noxious stimulation. However, whether the metabotropic glutamate receptor 7 (mGluR7) can modulate the pain-evoked electrical activities of pain-excited neurons and pain-inhibited neurons in the hippocampal CA3 region is not clear. Objective: The study aimed to examine the effects of mGluR7 allosteric agonist N,N'-dibenzhydrylethane-1,2-diamine dihydrochloride (AMN082) and antagonist 6-(4-methoxyphenyl)-5-methyl-3-pyridin-4-ylisoxazolo[4,5-c]pyridin-4(5H)-one (MMPIP) on the pain-evoked electrical activities of pain-excited neurons and pain-inhibited neurons in the CA3 region of rats. Method: A train of electric impulses applied to the sciatic nerve were used for noxious stimulation. The bio-electrical activities of pain-excited neuron or pain-inhibited neuron in the CA3 region were recorded by a glass microelectrode. Results: Our results exhibited that intra-CA3 region administration of the glutamic acid or AMN082 increased the pain-evoked discharged frequency and shortened the latency of pain-excited neuron, while decreased the pain-evoked discharged frequency and prolonged the inhibitory duration of paininhibited neuron in the CA3 region. The intra-CA3 region microinjection of MMPIP produced the opposite response. Conclusion: These findings demonstrated that the glutamic acid and mGluR7 in hippocampal CA3 region are involved in the modulation of nociceptive information transmission by regulating pain-evoked electric activities of pain-excited neurons and pain-inhibited neurons.

Objectives: This study investigated the neuroprotective effects of Jatrorrhizine in rat cortical neurons. Method: The effects of Jatrorrhizine on hydrogen peroxide (H2O2)-induced cell lesion, levels of lipid peroxidation and antioxidant enzyme activities were investigated in rat cortical neurons. Levels of mitochondrial membrane potential (MMP) and intracellular reactive oxygen species (ROS) were measured by fluorescent rhodamine staining and 2',7'-dichlorfluorescein-diacetate staining, respectively. ATP content was measured by a high performance liquid chromatography. The protein levels for Bax, Bcl2 and cleaved caspase-3 were analyzed by western blot protein expression. Results: There was a significant reduction in cell viability and activities of Superoxide dismutase and glutathione peroxidase for the cortical neurons after exposure to 50μM H2O2 for 12h. The hydrogen peroxide increased the production of malondialdehyde and ROS but decreased MMP and ATP in the neurons. However, pretreatment with different concentrations of Jatrorrhizine (5-20μM) inhibited H2O2-induced neurotoxicity markedly. Jatrorrhizine also attenuated the H2O2-induced Bcl-2/Bax ratio reduction and caspase-3 activation in these neurons. Conclusions: Our findings suggest that Jatrorrhizine plays a critical neuroprotective role in H2O2 - induced apoptosis through its anti-oxidative actions. This may allow Jatrorrhizine to be a novel therapeutic with its high bioavailability to treat Alzheimer's disease.

Background: Inflammatory responses are important mechanisms that are involved in cerebral ischemia/reperfusion(I/R) injury. Whether toll-like receptor 9(TLR9), which belongs to the innate immune system, takes part in the inflammatory responses following cerebral I/R remains unclear. Method: This study examined the effect of different dosages of the TLR9 antagonist inhibitory oligodeoxynucleotide (iCpG-ODN) on cerebral I/R injury by using a mouse model of transient middle cerebral artery occlusion. Neurological function, infarct size, splenocytes and the expression of TLR9 and the downstream products of the TLR9 pathways were determined after cerebral I/R for up to 72 hours. Results: The Clark's focal symptom scoring showed iCpG-ODN improved neurological deficits following focal cerebral I/R. The iCpG-ODN administration significantly decreased the infarct size in a dose-dependent manner. RT-PCR showed that iCpG-ODN attenuated the I/R-induced RNA expression of TLR9. Immunoblot showed that iCpG-ODN prevented I/R-induced increases in NFΚB and IRF7 levels and that it further downregulated the levels of IL-1β, TNF-α, and INF-β in the brain. iCpG-ODN did not alter the levels of TNF-α or INF-β in the peripheral blood or affect stroke-induced changes in the number of splenocytes. Conclusion: These findings suggest that iCpG-ODN induced protection against cerebral I/R via inhibiting inflammatory responses in a dose-dependent manner and may be useful in therapy for stroke patients.