Enhancing effects of acute exposure to cannabis smoke on working memory performance.

Numerous preclinical studies show that acute cannabinoid administration impairs cognitive performance. Almost all of this research has employed cannabinoid injections, however, whereas smoking is the preferred route of cannabis administration in humans. The goal of these experiments was to systematically determine how acute exposure to cannabis smoke affects working memory performance in a rat model. Adult male (n = 15) and female (n = 16) Long-Evans rats were trained in a food-motivated delayed response working memory task. Prior to test sessions, rats were exposed to smoke generated by burning different numbers of cannabis or placebo cigarettes, using a within-subjects design. Exposure to cannabis smoke had no effect on male rats' performance, but surprisingly, enhanced working memory accuracy in females, which tended to perform less accurately than males under baseline conditions. In addition, cannabis smoke enhanced working memory accuracy in a subgroup of male rats that performed comparably to the worst-performing females. Exposure to placebo smoke had no effect on performance, suggesting that the cannabinoid content of cannabis smoke was critical for its effects on working memory. Follow-up experiments showed that acute administration of either Δ9-tetrahydrocannabinol (0.0, 0.3, 1.0, 3.0 mg/kg) or the cannabinoid receptor type 1 antagonist rimonabant (0.0, 0.2, 0.6, 2.0 mg/kg) impaired working memory performance. These results indicate that differences in the route, timing, or dose of cannabinoid administration can yield distinct cognitive outcomes, and highlight the need for further investigation of this topic.

Cannabis Oil Use by Adolescents and Young Adults With Inflammatory Bowel Disease.

OBJECTIVES: The aim of the study was to describe use of oral or sublingual cannabis oil (CO) by adolescent and young adult patients with inflammatory bowel disease (IBD). METHODS: A descriptive study of IBD patients 13 to 23 years of age seen between January 2015 through December 2017 at Children's Hospital Colorado. Information obtained included chart abstraction, electronic and interview self-report, and serum cannabinoid levels. We compared CO users and cannabis non-users for clinical characteristics and perceptions of risk. Users of CO provided information on routes, patterns, motivations, and perceived benefits and problems with use. RESULTS: The 15 users and 67 non-users were similar for clinical characteristics and pain and appetite scores. 9 of 15 (60%) CO users had used in the past 30 days, an average of 22 ±â€Š9 times; and 4 used daily. A variety of strengths and CBD:THC ratios were reported. Most common perceived effect of use was on sleep quality, nausea, and increase in appetite. Of the 15 users, 6 used only CO and no additional forms of cannabis. Of these 6 CO only users, 5 reported a medical reason for use, most commonly to relieve pain. CONCLUSIONS: Adolescent and young adults with IBD used oral CO and many used other cannabis products as well. Users perceived some medical benefit. Care teams should strive for open communication about use until further information on safety and efficacy becomes available.

Cannabinoid CB1 Discrimination: Effects of Endocannabinoids and Catabolic Enzyme Inhibitors.

An improved understanding of the endocannabinoid system has provided new avenues of drug discovery and development toward the management of pain and other behavioral maladies. Exogenous cannabinoid type 1 (CB1) receptor agonists such as Δ9-tetrahydrocannabinol are increasingly used for their medicinal actions; however, their utility is constrained by concern regarding abuse-related subjective effects. This has led to growing interest in the clinical benefit of indirectly enhancing the activity of the highly labile endocannabinoids N-arachidonoylethanolamine [AEA (or anandamide)] and/or 2-arachidonoylglycerol (2-AG) via catabolic enzyme inhibition. The present studies were conducted to determine whether such actions can lead to CB1 agonist-like subjective effects, as reflected in CB1-related discriminative stimulus effects in laboratory subjects. Squirrel monkeys (n = 8) that discriminated the CB1 full agonist AM4054 (0.01 mg/kg) from vehicle were used to study, first, the inhibitors of fatty acid amide hydrolase (FAAH) or monoacylglycerol lipase (MGL) alone or in combination [FAAH (URB597, AM4303); MGL (AM4301); FAAH/MGL (JZL195, AM4302)] and, second, the ability of the endocannabinoids AEA and 2-AG to produce CB1 agonist-like effects when administered alone or after enzyme inhibition. Results indicate that CB1-related discriminative stimulus effects were produced by combined, but not selective, inhibition of FAAH and MGL, and that these effects were nonsurmountably antagonized by low doses of rimonabant. Additionally, FAAH or MGL inhibition revealed CB1-like subjective effects produced by AEA but not by 2-AG. Taken together, the present data suggest that therapeutic effects of combined, but not selective, enhancement of AEA or 2-AG activity via enzyme inhibition may be accompanied by CB1 receptor-mediated subjective effects.

Interaction of plant cannabinoids with the multidrug transporter ABCC1 (MRP1).

The ATP-binding cassette (ABC) transporter ABCC1, or multidrug resistance-related protein 1 (MRP1) is implicated in Phase II metabolism and multidrug resistance as it effluxes substrate anticancer drugs. As cannabinoids inhibit two related ABC transporters, P-glycoprotein and ABCG2, here we examined whether they also inhibit ABCC1. Indeed, the cannabinoids enhanced the intracellular accumulation of two ABCC1 substrates, Fluo3 and vincristine, in ovarian carcinoma cells over-expressing ABCC1 (2008/MRP1) with a rank order of potency: cannabidiol>cannabinol>Delta(9)-tetrahydrocannabinol. Cannabinoid inhibition of ABCC1 was confirmed using insect cell membrane MRP1 ATPase assays. These results demonstrate that cannabinoids inhibit ABCC1.

Potent Anti-Inflammatory and Pro-Resolving Effects of Anabasum in a Human Model of Self-Resolving Acute Inflammation.

Anabasum is a synthetic analog of Δ8 -tetrahydrocannabinol (THC)-11-oic acid that in preclinical models of experimental inflammation exerts potent anti-inflammatory actions with minimal central nervous system (CNS) cannabimimetic activity. Here we used a novel model of acute inflammation driven by i.d. UV-killed E. coli in healthy humans and found that anabasum (5 mg) exerted a potent anti-inflammatory effect equivalent to that of prednisolone in terms of inhibiting neutrophil infiltration, the hallmark of acute inflammation. These effects arose from the inhibition of the neutrophil chemoattractant LTB4 , while the inhibition of antiphagocytic prostanoids (PGE2 , TxB2 , and PGF2 α) resulted in enhanced clearance of inflammatory stimulus from the injected site. Anabasum at the higher dose of 20 mg possessed the additional properties of triggering the biosynthesis of specialized pro-resolving lipid mediators including LXA4 , LXB4 , RvD1, and RvD3. Collectively, we demonstrate for the first time a striking anti-inflammatory and pro-resolution effects of a synthetic analog of THC in healthy humans.

Pharmacokinetics and metabolism of the plant cannabinoids, delta9-tetrahydrocannabinol, cannabidiol and cannabinol.

Increasing interest in the biology, chemistry, pharmacology, and toxicology of cannabinoids and in the development of cannabinoid medications necessitates an understanding of cannabinoid pharmacokinetics and disposition into biological fluids and tissues. A drug's pharmacokinetics determines the onset, magnitude, and duration of its pharmacodynamic effects. This review of cannabinoid pharmacokinetics encompasses absorption following diverse routes of administration and from different drug formulations, distribution of analytes throughout the body, metabolism by different tissues and organs, elimination from the body in the feces, urine, sweat, oral fluid, and hair, and how these processes change over time. Cannabinoid pharmacokinetic research has been especially challenging due to low analyte concentrations, rapid and extensive metabolism, and physicochemical characteristics that hinder the separation of drugs of interest from biological matrices--and from each other--and lower drug recovery due to adsorption of compounds of interest to multiple surfaces. delta9-Tetrahydrocannabinol, the primary psychoactive component of Cannabis sativa, and its metabolites 11-hydroxy-delta9-tetrahydrocannabinol and 11-nor-9-carboxy-tetrahydrocannabinol are the focus of this chapter, although cannabidiol and cannabinol, two other cannabinoids with an interesting array of activities, will also be reviewed. Additional material will be presented on the interpretation of cannabinoid concentrations in human biological tissues and fluids following controlled drug administration.

Human skin permeation of Delta8-tetrahydrocannabinol, cannabidiol and cannabinol.

The purpose of this study was to quantify the in-vitro human skin transdermal flux of Delta8-tetrahydrocannabinol (Delta8-THC), cannabidiol (CBD) and cannabinol (CBN). These cannabinoids are of interest because they are likely candidates for transdermal combination therapy. Differential thermal analysis and in-vitro diffusion studies with human tissue were completed for the compounds. Heats of fusion, melting points and relative thermodynamic activities were determined for the crystalline compounds, CBD and CBN. Flux, permeability, tissue concentration and lag times were measured in the diffusion experiments. CBN had a lower heat of fusion and corresponding higher calculated relative thermodynamic activity than CBD. Ethanol concentrations of 30 to 33% significantly increased the transdermal flux of Delta8-THC and CBD. Tissue concentrations of Delta8-THC were significantly higher than for CBN. Lag times for CBD were significantly smaller than for CBN. The permeabilities of CBD and CBN were 10-fold higher than for Delta8-THC. Combinations of these cannabinoids with ethanol will be further studied in transdermal patch formulations in vitro and in vivo, as significant flux levels of all the drugs were obtained. CBD, the most polar of the three drugs, and other more polar cannabinoids will also be the focus of future drug design studies for improved transdermal delivery rates.

Potent inhibition of human cytochrome P450 3A isoforms by cannabidiol: role of phenolic hydroxyl groups in the resorcinol moiety.

AIMS: In this study, we examined the inhibitory effects of Δ(9)-tetrahydrocannabinol (Δ(9)-THC), cannabidiol (CBD), and cannabinol (CBN), the three major cannabinoids, on the activity of human cytochrome P450 (CYP) 3A enzymes. Furthermore, we investigated the kinetics and structural requirement for the inhibitory effect of CBD on the CYP3A activity. MAIN METHODS: Diltiazem N-demethylase activity of recombinant CYP3A4, CYP3A5, CYP3A7, and human liver microsomes (HLMs) in the presence of cannabinoids was determined. KEY FINDINGS: Among the three major cannabinoids, CBD most potently inhibited CYP3A4 and CYP3A5 (IC(50)=11.7 and 1.65 µM, respectively). The IC(50) values of Δ(9)-THC and CBN for CYP3A4 and CYP3A5 were higher than 35 µM. For CYP3A7, Δ(9)-THC, CBD, and CBN inhibited the activity to a similar extent (IC(50)=23-31 µM). CBD competitively inhibited the activity of CYP3A4, CYP3A5, and HLMs (K(i)=1.00, 0.195, and 6.14 µM, respectively). On the other hand, CBD inhibited the CYP3A7 activity in a mixed manner (K(i)=12.3 µM). Olivetol partially inhibited all the CYP3A isoforms tested, whereas d-limonene showed lack of inhibition. The lesser inhibitory effects of monomethyl and dimethyl ethers of CBD indicated that the ability of CYP3A inhibition by the cannabinoid attenuated with the number of methylation on the phenolic hydroxyl groups in the resorcinol moiety. SIGNIFICANCE: This study indicated that CBD most potently inhibited catalytic activity of human CYP3A enzymes, especially CYP3A4 and CYP3A5. These results suggest that two phenolic hydroxyl groups in the resorcinol moiety of CBD may play an important role in the CYP3A inhibition.

Single-dose kinetics of deuterium-labelled cannabinol in man after intravenous administration and smoking.

The single dose pharmacokinetics of deuterium-labelled cannabinol (2H2-CBN) were evaluated in six male cannabis users with different degree of abuse after smoking an average dose of 19 mg and after intravenous administration of 20 mg CBN. Plasma levels were measured for up to 72 h with selected ion monitoring by GC/MS using 2H7-CBN as internal standard. The systemic availability of smoked CBN was found to be 39 +/- 26% (min-max 6-65%). The mean plasma clearance was 19.1 +/- 2.6 ml min-1 kg-1 and the volume of distribution was determined to 50 +/- 23 l kg-1. The apparent terminal half lives for CBN were 32 +/- 17 h and 43 +/- 29 h after intravenous administration and smoking, respectively.

Comparative diuretic activity of delta9-tetrahydrocannabinol, cannabidiol, cannabinol and hydrochlorothiazide in the rat.

Orally administered delta9-tetrahydrocannabinol (THC) produced a dose-dependent increase in urine output in hydrated rats similar in mg/kg potency and magnitude of effect to hydrochlorothiazide (HCT). Whereas HCT promoted marked excretion of Na+, K+ and Cl- and an increase in the urinary Na+/K+ at all diuretic doses (1.25-20.0 mg/kg), THC had only a slight effect on Na+ and K+ excretion but not Cl- even after the highest dose tested (20.0 mg/kg). Hypophysectomy and adrenalectomy abolished the diuretic effect of THC, thus suggesting both central and peripheral sites of action for the diuretic effect of THC. Tolerance to the effect on urine output by THC developed after 15 days of repeated dosing, while urine output and electrolyte excretion remained significantly elevated after 25 days of HCT administration.

Synthesis and pharmacological effects in mice of halogenated cannabinol derivatives.

Eight halogenated derivatives of cannabinol (CBN) substituted on the aromatic ring at the 2 and/or 4 position were synthesized and their pharmacological effects were evaluated by intracerebroventricular injection (50 micrograms/mouse) in mice, using hypothermia, pentobarbital-induced sleep prolongation, catalepsy and anticonvulsant effect as indices. The hypothermic effects of monohalogenated derivatives of CBN were comparable to that of CBN, whereas the effects of dihalogenated derivatives of CBN except for the fluorinated derivative were attenuated. In the interaction with pentobarbital, two monochlorinated derivatives exhibited a significant prolongation of sleeping time, although other derivatives did not significantly affect the sleeping time. The cataleptogenic effects of monofluoro- and 4-bromo-CBN were stronger than that of CBN. 4-Bromo-CBN exhibited a significant prolongation of seizure latency induced by pentylenetetrazol. These data suggest that halogenation of CBN modifies the pharmacological profile of the cannabinoid.

Attenuation of the ovalbumin-induced allergic airway response by cannabinoid treatment in A/J mice.

T cells are sensitive to modulation by cannabinoids as evidenced by their ability to inhibit expression of cytokines, including interleukin (IL)-2 and IL-4. Because T cells play a key role in the pathophysiology of allergic asthma by expressing T helper cell (Th)2 cytokines, the objective of the present studies was to examine the effect of cannabinoids on immunologic and pathologic features associated with the allergic airway response induced by ovalbumin (Ova). A/J mice were systemically sensitized with Ova and subsequently challenged with aerosolized Ova. The steady-state mRNA expression of IL-2 and Th2 cytokines (IL-4, IL-5, and IL-13) was markedly increased in the lungs of Ova-sensitized mice 24 h after a single Ova challenge. Concordantly, the level of total and Ova-specific serum immunoglobulin (Ig)E and intraepithelial mucosubstances in the axial intrapulmonary airway of Ova-sensitized mice was robustly elevated 96 h after the second Ova challenge. Cannabinol (CBN) or Delta(9)-tetrahydrocannabinol (Delta(9)-THC; 50 mg/kg, ip), administered daily for 3 consecutive days before sensitization and then before challenge, significantly attenuated the elevation of IL-2, IL-4, IL-5, and IL-13 steady-state mRNA expression elicited by Ova challenge in the lungs. In addition, the elevation of serum IgE and the mucus overproduction induced by Ova challenge was also markedly attenuated by CBN or Delta(9)-THC administration in Ova-sensitized mice. These results suggest that plant-derived immunomodulatory cannabinoids exhibit potential therapeutic utility in the treatment of allergic airway disease by inhibiting the expression of critical T cell cytokines and the associated inflammatory response.

Effect of cannabinoids on spermatogenesis in vivo: a cytological study.

The cytogenetic effects of delta 9-tetrahydrocannabinol (THC) and cannabinol (CBN) (10 mg/kg) were investigated in hybrid mice of genotype (C57BL x C3H)F1. Mice were treated for 5 consecutive days with the specific cannabinoid; 16 days after the last treatment the meiotic cells were evaluated. Analysis of the spermatocyte bivalents at the first meiotic metaphase failed to reveal any numerical or structural abnormality. Contrary to previous reports we failed to find any major meiotic abnormalities associated with THC and CBN treatments. There was no evidence of ring or chain figures. The centromeric banding procedure (C banding) was used to support observations of Giemsa stained cells. It has previously been reported that cannabinoids suppress the incorporation of 3H-uridine into pachytene spermatocytes and round spermatids; the absence of chromosome aberrations in the present study suggests that an adverse effect appears to be present, but may be at a level other than cytogenetic.

Effects of delta-9-tetrahydrocannabinol, cannabinol and cannabidiol, alone and in combinations, on luteinizing hormone and prolactin release and on hypothalamic neurotransmitters in the male rat.

The acute effects of low oral doses of delta 9-tetrahydrocannabinol (THC), cannabinol (CBN) and cannabidiol (CBD) administered alone or in combinations on LH and prolactin (PRL) secretion and on hypothalamic norepinephrine (NE), dopamine (DA) and serotonin (5-HT) dynamics were examined in adult male rats. Plasma LH levels were significantly reduced 60 min after administration of 0.5 mg THC/kg body weight and 30, 60 and 120 min after administration of THC + CBN or THC + CBD. There were no changes in plasma PRL in response to cannabinoid treatments. The turnover of NE in both the median eminence (ME) and medial basal hypothalamus (MBH) was dramatically affected by all the cannabinoid treatments. Complete suppression of NE turnover occurred 30 min post-THC and 120 min post-THC + CBN in the ME and 120 min post-THC + CBD in the MBH. Cannabinoids did not significantly affect DA turnover in the MBH or the content of NE, DA, 5-HT or 5-hydroxyindole-3-acetic acid in either the ME or MBH. These data demonstrate that treatment of adult male rats with a low dose of THC suppresses LH secretion and that CBN and CBD potentiate this action of THC. Although the mechanisms responsible for the inhibition of LH release by cannabinoids cannot be positively identified from these experiments, the results suggest that alterations in hypothalamic noradrenergic activity may be involved in this effect.