Whether chronic marijuana (MJ) use adversely affects human brain function remains controversial. Using [15O] water PET, regional cerebral blood flow during selective attention was compared in R-handed MJ users (9 M, 9 F; mean ± SD age, 22.3 ± 2.2 y) and controls (6 M, 7 F; 22.6 ± 1.9 y). The users had been using MJ ≥7 times weekly on average for ≥2 y (mean, 3.9 ± 1.8 y). The controls had never or rarely used MJ. Following MRI, and after ≥26 h of monitored abstention, subjects performed dichotic listening tests using nonsense word stimuli while being imaged with PET. The tests were modifications of previous ones used by our group (O'Leary et al. (1996) Brain Lang 53: 20-39). During separate tests, attention was directed to the L and R ears. A control test, choice reaction time (missing for 2 subjects), was used to control for auditory stimulation and motor responses. Within group subtractions of the control test from the attention tests showed major attention-related activations in auditory cortex, i.e., su...

Depression is highly incident in the diabetic patients. It is known that several antidepressant drugs used to treat depression may alter the blood glucose or even interact with hypoglycemic drugs. Thus, the search for a more effective treatment for the ...

Cannabis and ecstasy (MDMA) are two of the most widely used recreational drugs often taken in combination by drug users. The aim of the present study was to investigate whether subthreshold doses of MDMA and delta9-tetrahydrocannabinol (THC) produced synergistic rewarding effects in mice. A conditioned place preference paradigm (CPP) was used to assess the rewarding properties of MDMA (0, 3, and 10 mg/kg, i.p.) alone and in combination with THC (0 and 0.3 mg/kg, i.p.). In addition, in vivo microdialysis in freely moving mice was performed in order to evaluate changes in extracellular dopamine levels in the nucleus accumbens following single or combined administration of MDMA (0 and 3 mg/kg) and THC (0 and 0.3 mg/kg). MDMA at the dose of 10 mg/kg produced a significant CPP, while neither MDMA (3 mg/kg) nor THC (0.3 m/kg) produced this effect. The combination of ineffective doses of MDMA and THC induced a significant CPP compared to each drug given by itself. However, THC did not potentiate the CPP produced ...

Current findings demonstrate that cannabinoids (CBs) can elicit both neuroprotection and neuromodulation, although detailed mechanisms remain to be elucidated. Here we investigated whether the non-psychotropic plant cannabinoid, cannabidiol (CBD), can modulate Ca2+ signalling in hippocampal cells. Hippocampi of Sprague-Dawley neonates (1-3 days) were dissected and the tissue enzymatically dissociated. Cultures were matured for 5-12 days and loaded with the fluorescent Ca2+ indicator Fura-2AM (6–10 µM). Dishes were perfused with HEPES buffered solution (containing 0.5 µM TTX) and images captured at 350 and 380 nm to calculate [Ca2+]i measurements as ratio units. CBD application (1 µM) induced a Ca2+ response in both neurones and glia (46% and 83%, respectively). Interestingly, the CBD-induced Ca2+ response was significantly enhanced by the CB1 antagonist AM281 (1 µM, 400%) and in cultures pre-incubated with the Gi/o protein blocker, pertussis toxin (PTX, 100 ng/ml, 300%), indicative of a CB1 receptor depend...

Objective: Cannabidiol (CBD) a non-psychoactive component of marijuana, prevents glutamate-mediated neurotoxicity and reactive oxygen species induced cell death in neuronal culture. This study was designed to evaluate the neuroprotective efficacy of CBD in a model of global cerebral ischemia in dogs. Methods: 18 adult female Beagles underwent 10 min Cardiac Arrest. then restoration of spontaneous circulation followed by 24 hours of intensive care. Immediately following resuscitation, half of the animals received CBD (5 mg/kg IV) while the others received drug vehicle only. 23 hr after resuscitation, dogs were awakened and examined for neurologic deficit by blinded examiners using a standardized neurologic deficit scoring (NDS) system, measuring level of consciousness, respiration, cranial nerves, motor/sensory function and behavior. (0 = nl, 100 = brain death). NDS has previously been shown to correlate with neuronal histopathology. Results: No differences were noted between experimental groups in terms of...

Background: Recently, there has been an increased interest in exploiting the therapeutic properties of cannabis and its derivatives, even if their precise therapeutic indications have not yet been completely elucidated in preclinical and clinical studie...

The legalization and increased use of cannabis and its main constituent ∆9-tetrahydrocannabinol (THC), as a recreational and medicinal drug, has enhanced research interest related to the potential interactions of cannabis use and other psychological con...

Adolescence is a neurodevelopmental period in which cortico-limbic circuitry has not yet reached maturation, likely resulting in greater difficulty with regulation of appetitive behavior. Marijuana use is increasing among adolescents, and behavioral str...

Cannabis dependence can be inferred from tolerance and withdrawal symptoms following repeated exposure. In rodents, cannabinoid withdrawal is commonly quantified using somatic signs, for example frequency of paw tremors and head twitches. Two critiques ...

The ventral tegmental area (VTA) is the reward center of the brain where synaptic plasticity is at the root of many learned behaviors, including maladaptive forms of drug dependence and addiction reinforcement. Used for recreation or for pain modulation...