Investigation of chloroplast regions rps16 and clpP for determination of Cannabis sativa crop type and biogeographical origin

Cannabis sativa can be classified as either hemp (a legal crop containing less than 0.3% delta-9-tetrahydrocannabinol, THC) or marijuana (an illegal drug containing more than 0.3% THC). Despite its legalization in 33 states for medicinal or recreational use, marijuana remains the most commonly used illicit drug in the USA, and it is heavily trafficked into and within the country. Discriminating between marijuana and hemp is critical to the legal process. Genetic analysis provides a means of analyzing samples unsuitable for chemical analysis, and in addition to discriminating between crop types, DNA may be able to determine the biogeographical origin of samples. In addition, the sharing of rare haplotypes between different seizures may be useful for linking cases and providing investigative leads to law enforcement. This study evaluates the potential of two highly polymorphic regions of the chloroplast genome of C. sativa, rps16 and clpP, to be used for determination of crop type and biogeographical origin. Custom fragment analysis and SNaPshot™ assays were developed to genotype nine polymorphic loci in hemp samples from the USA and Canada, marijuana samples from USA-Mexico and Chile, and medical marijuana samples from Chile. Haplotype analysis revealed eight haplotypes. Only Canadian hemp could be completely differentiated from the other sample groups by haplotype. Phylogenetic analysis and principal component analysis suggested a closer relationship among USA-Mexico marijuana, Chilean marijuana and medical marijuana, and USA hemp. Genotyping additional polymorphisms in future studies is expected to reveal further differences between these sample groups.     

Delta-9-tetrahydrocannabinol content and human marijuana self-administration

The role of marijuana delta-9-tetrahydrocannabinol (THC) content in controlling marijuana smoking behavior was examined in ten regular marijuana smokers. Each subject was allowed to self-administer marijuana of low, medium or high THC content freely over a 30-min period. Each potency of marijuana was color coded, and subjects smoked each potency on five separate occasions to provide the opportunity for them to learn from prior exposures the relative potencies of each marijuana type. Total intake of marijuana smoke during each session was estimated by measuring the post-smoking increase in expired air carbon monoxide (CO) level. Measures of marijuana effect included heart rate and standardized subjective effects scales. There were no differences among the three potencies of marijuana in post-smoking CO boost, and all measures that were sensitive to marijuana showed a clear dose response. Tolerance was observed over the course of the study to the heart-rate increasing effect of marijuana. These results indicate that subjects failed to regulate their intake of marijuana smoke in response to substantial (4-fold) changes in marijuana THC content.     

Physical withdrawal in rats tolerant to Δ-tetrahydrocannabinol precipitated by a cannabinoid receptor antagonist

Tolerance to Δ⁹-tetrahydrocannabinol (Δ⁹-THC) was produced in rats by twice daily injections (15 mg/kg i.p.) for 6.5 days. Administration of the cannabinoid antagonist SR141716A (i.p. or i.c.v.) induced a profound precipitated withdrawal syndrome in Δ⁹-THC-tolerant animals. The syndrome was characterized by a disorganized pattern of constantly changing brief sequences of motor behavior. Autonomic signs were not evident. THC-tolerant animals that were treated with vehicle remained quiet throughout the observation period.     

Multidimensional behavioral effects of marijuana

Kelly Thomas H., Richard W. Foltin, Cleeve S. Emurian and Marian W. Fischman: Multidimensional Behavioral Effects of Marijuana. Prog. Neuro-Psychopharmacol. & Biol. Psychiat. 1990, : 885–902.

1. 1. Five groups of three healthy adult male volunteers (n = 15), all reporting occasional, controlled marijuana use, gave written consent and participated in residential studies lasting 6 to 15 days.

2. 2. Subjects smoked marijuana cigarettes (0 1.3 2.3 or 2.7% THC, w/w) at 0945, 1330, 1700 and 2030 every day, and each subject received both active and placebo marijuana cigarettes in 2–5 consecutive day phases, with placebo and active doses presented in an alternating fashion.

3. 3. In comparison with placebo, active marijuana produced a variety of effects on measures of human behavior, including in food consumption and errors on psychomotor tasks, in bouts of tobacco-cigarette smoking and verbal interactions and in rates of task performance, time spent under social conditions or social cooperation.

4. 4. Dimensions of human behavior were differentially sensitive to the effects of smoked marijuana.

5. 5. The simultaneous measurement of multiple dimensions of human behavior is a useful procedure for determining dose potency following marijuana administration.

Evidence for separate neuronal mechanisms for the discriminative stimulus and catalepsy induced by Δ9-THC in the rat

The cataleptogenic effect of ⁹-THC was compared to its discriminative stimulus effects in rats. The ED₅₀s for the discriminative stimulus and catalepsy were 0.8 and 4.0 mg/kg, respectively, while their time courses were very similar. The ED₅₀ of ⁹-THC for catalepsy in experimentally naive rats was not different from that in rats trained with the drug discrimination procedure, indicating that the cataleptogenic effect was not appreciably attenuated by long-term exposure to low doses of ⁹-THC. Pharmacologically, the catalepsy produced by ⁹-THC more closely resembled that of haloperidol than of morphine, since anticholinergic pretreatment eliminated the ⁹-THC-induced catalepsy while pre-treatment with naloxone had no effect. Although the cataleptogenic effect of ⁹-THC could be pharmacologically manipulated by anticholinergic pre-treatment, its discriminative stimulus effects were not changed in the same animals. These results demonstrate that distinctive mechanisms of action exist for these cannabinoid-induced behaviors.     

Cannabis use and bariatric surgery psychology practice: survey and insights

BackgroundCannabis is second only to alcohol as a substance of abuse and dependence in the United States. While there is extensive research examining alcohol use and bariatric surgery, there is currently little research and there are no published guidelines specific to cannabis use and bariatric surgery.ObjectivesTo identify major themes and general guidelines applied by bariatric surgery psychology clinicians.SettingThis practice survey was disseminated to bariatric surgery psychologists at various U.S. academic medical centers, hospitals, and private practices.MethodsAn electronic, 35-question survey was sent to 47 bariatric surgery psychologists to collect information on current clinical practice guidelines regarding cannabis use before and after bariatric surgery.ResultsThe survey questionnaire was completed by 34 (72.34%) bariatric surgery psychologists. The major identified themes included: (1) the lack of a standardized assessment of cannabis use; (2) a requirement for 3 months of abstinence from cannabis before bariatric surgery; (3) recommended lifetime abstinence from cannabis after bariatric surgery; and (4) discussion of cannabis use risks following bariatric surgery, including appetite stimulation, addiction potential, and possible negative impacts on judgment.ConclusionCannabis use will likely further increase in the United States. This survey highlighted common bariatric surgery psychology practices in the absence of extensive research and published guidelines. These findings suggest a preliminary framework with which to address cannabis use in patients seeking bariatric surgery. It is recommended that professional organizations and societies build on these initial survey findings to develop guidelines for more consistent, evidence-based practice regarding cannabis use and bariatric surgery.     

Marijuana use in adolescence

The prevalence of marijuana use by adolescents has fluctuated in recent decades, but, overall, has increased significantly. In a study of adolescent health status and risk behaviours among students in grades 7 to 12 in British Columbia, it was found that the patterns of marijuana use had changed, especially among early adolescents. An earlier age of onset of use and an increased frequency of use were noted. The present paper examines the clinical and psychosocial implications of early age of onset of marijuana use, and reports important differences in risky behaviours between users and nonusers. The prevailing attitude that marijuana is a ‘safe, recreational’ drug is challenged.     

Trends of Youth Marijuana Treatment Admissions: Increasing Admissions Contrasted with Decreasing Drug Involvement

Background: Recent changes in marijuana policies and their potential negative effects on youth development are a public health concern. Identifying the most appropriate treatment approaches for problematic marijuana use is important. Objectives: The aim of this study was to track marijuana use among young people by examining national changes from 1995 to 2012 in the demographics, referral sources, and the substance use patterns related to youth admissions to substance abuse treatment programs. Methods: We examined first-time substance abuse treatment admissions among youth, utilizing the Treatment Episode Data Set - Admissions (TEDS-A) of the Substance Abuse Mental Health Services Administration (N = 12,025,787). Chi-squared analysis was used to examine differences between admission years and binomial logistic regression was used to examine trends over the 18 years. Results: We found increasing numbers of youth in dependent living situations (e.g. with parents) admitted to substance use disorder treatment for marijuana. We also found a dramatic drop in the degree of drug involvement for those admissions over nearly two decades of data. Conclusions/Importance: While availability and changing perceptions of marijuana might have caused an increase in admissions to substance abuse treatment, our findings indicate that the severity of drug use involved in those admissions has decreased. This study highlights the importance of identifying youth in actual need of treatment services and not overlooking tools such as screening, brief intervention, and motivational interviewing as effective for varying levels of marijuana use by youth.     

Δ9-Tetrahydrocannabinol produces naloxone-blockable enhancement of presynaptic basal dopamine efflux in nucleus accumbens of conscious,freely-moving rats as measured by intracerebral microdialysis

This study examined the effects of acute administration of delta-9-tetrahydrocannabinol (⁹-THC), the psychoactive ingredient in marijuana, on extracellular efflux of dopamine (DA) and its metabolites as measured by in vivo microdialysis in nucleus accumbens of conscious, freely-moving rats. ⁹-THC, at low doses (0.5–1.0 mg/kg), which significantly enhance brain stimulation reward (intracranial self-stimulation), significantly increased DA efflux in nucleus accumbens. Augmentation of DA efflux by ⁹-THC was abolished by removal of calcium (Ca⁺⁺) ions from the perfusion fluid, indicating a Ca⁺⁺-dependence of ⁹-THC's action. Augmentation of DA efflux by ⁹-THC was either totally blocked or significantly attenuated by doses of naloxone as low as 0.1 mg/kg. Given the postulated role of mesocorticolimbic DA circuits in mediating and/or modulating brain stimulation reward, the present data raise the possibility that marijuana's rewarding effects, and hence its euphorigenic effects and abuse potential, may be related to pharmacological augmentation of presynaptic DA mechanisms. Additionally, the DA mechanisms enhanced by marijuana appear to be modulated by an endogenous opioid peptide system.