Anticonvulsant properties of delta 9-tetrahydrocannabinol and other cannabinoids

Anticonvulsant doses of Δ⁹-tetrahydrocannabinol (Δ⁹-THC) markedly lower body temperature in mice at an ambient temperature of 22°C, but there is little such effect at 30°C. The anticonvulsant properties of Δ⁹-THC are as follows: The drug abolishes hind-limb extension in a maximal electroshock (MES) test, elevates both the MES (extensor) and 6-Hz-electroshock thresholds, exerts no effect on the 60-Hz-electroshock threshold, and enhances minimal seizures caused by pentylenetetrazol. All anticonvulsant properties studied, with the exception of the 60-Hz-electroshock threshold, were unaffected by the hypothermia resulting at 22°C. Additional experiments with Δ⁹-THC indicated that chronic treatment results in the development of tolerance, as determined by the MES test with rats. The four principal naturally occurring cannabinoids, Δ⁹-THC, Δ⁸-THC, cannabinol and cannabidiol, display anticonvulsant activity, as does the major, primary metabolite of Δ⁹-THC, 11-hydroxy-Δ⁹-THC. Of all agents investigated in mice, the synthetic cannabinoids, dimethylheptylpyran and its isomers, are the most potent anticonvulsants. The results of a study of the relative motor toxicity and anticonvulsant activity of the cannabinoids demonstrate that these properties are at least partially separable among the various agents.     

Relationship between the subcellular distribution of delta-9-tetrahydrocannabinol and its metabolites in rat brain and the duration of the effect on motor activity.

Female rats were injected intraperitoneally with 10 mg/kg of unlabelled delta-9-tetrahydrocannabinol (Δ⁹-THC) and their locomotor activity was recorded every 15 minutes for 12 hours. The maximum depressant effect was observed between the first and fourth hour and had completely disappeared by the eighth hour of treatment. In parallel experiments rats were injected with 10 mg/kg of ³H-delta-9-THC and decapitated either one, four or twelve hours later. The concentrations of unchanged delta-9-THC and metabolites in brain subcellular fractions were determined using thin layer chromatographic methods. There were no substantial differences in the relative specific activities of delta-9-THC or 11-OH-delta-9-THC between all fractions except cytosol, indicating no preferential site of accumulation. However, when the synaptosomal fraction was osmotically shocked, the concentration of delta-9-THC in nerve-ending membranes was markedly higher than that in vesicles or soluble fraction. Our results $\text{in vivo}$ showed a marked decline, over twelve hours, in the relative specific activities of delta-9-THC and 11-OH-delta-9-THC with a concomitant increase in the concentration of highly polar, non-extractable metabolites in all subfractions. It is suggested that the diminution of the depressant effect on motor activity may be related to the formation of highly polar, pharmacologically inactive metabolites of delta-9-THC and/or 11-OH-delta-9-THC inside the brain which do not easily migrate out of the cells.     

Endocrine effects of chronic intraventricular administration of delta9-tetrahydrocannabinol to prepuberal and adult male rats.

The daily intraventricular administration of Δ⁹-tetrahydrocannabinol (Δ⁹-THC) in microgram amounts for a week to prepuberal and adult rats had definite endocrine effects. Prostate weights were reduced and plasma and pituitary levels of growth hormone (GH) were increased in prepuberal rats. Pituitary levels of prolactin (PRL) were increased both in prepuberal and in adult animals while pituitary and adrenal weights and plasma corticosterone (B) levels were increased in adult rats. On the other hand, brain weights were significantly reduced by Δ⁹-THC in prepuberal and significantly increased in adult animals. No changes in brain levels of noradrenaline (NA), dopamine (DA) or serotonin (5-HT) were found in treated animals. These results indicate that Δ⁹-THC may modify some endocrine functions when injected directly into the brain in microgram amounts. They show on the other hand that young and adult animals may respond differently to the chronic administration of the psychoactive drug, although the difference may be due to a biphasic effect of different doses.     

Hypothermic action of delta 9-tetrahydrocannabinol, 11-hydroxy-delta 9-tetrahydrocannabinol and 11-hydroxy-delta 8-tetrahydrocannabinol in mice

The hypothermic activity of Δ⁹-tetrahydrocannabinol (Δ⁹-THC), a metabolite, 11-hydroxy-Δ⁹-tetrahydrocannabinol (11-OH-Δ⁹-THC) and 11-hydroxy-Δ⁸-tetrahydrocannabinol (11-OH-Δ⁸-THC) has been determined in male mice maintained at an ambient temperature of 20 ± 1°C. The mean body temperature of mice that received 2, 4, 16 or 32 mg/kg, i. v., of a tetrahydrocannabinol was significantly lower than that of vehicle treated mice (p <0.05) within 2 minutes after drug administration. Dose-response relationships show the intrinsic activity of Δ⁹-THC to be significantly greater than that of 11-OH-Δ⁹-THC or 11-OH-Δ⁸-THC in this system (p <0.05). The data indicate that the hypothermic activity of Δ⁹-THC cannot be explained entirely by metabolism to 11-OH-Δ⁹-THC.     

Δ9-tetrahydrocannabinol and dimethylheptylpyran induced tachycardia in the conscious rat

Since cannabinoids lead to dose-related tachycardia in man but dose dependent bradycardia has been reported thus far in laboratory animals, there would seem to be a need for an experimental model in which the effect seen in man (tachycardia) could be reproduced and explored. In the conscious rat, the compounds Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and dimethylheptylpyran (DMHP) injected i.p. led to dose-related increases in heart rate at 10–20 minutes after administration. In vehicle (ethanol) control rats there were small increases in heart rate. Propranolol given before Δ⁹-THC resulted in a parallel shift to the right of the dose-effect curve. Adrenalectomy led to a significant (p<0.01) decrease in tachycardia following Δ⁹-THC and DMHP while ganglionic block markedly decreased the heart rate increases after Δ⁹-THC (p<0.001). Systolic blood pressure at nearly all doses of Δ⁹-THC was minimally affected, although it tended to decrease with increasing dose. Tachycardia in the rat may be the result of a centrally mediated release of epinephrine from the adrenal gland.     

Effects of Δ9-tetrahydrocannabinol on neurotransmitter accumulation and release mechanisms in rat forebrain synaptosomes

The effects of (?)?Δ⁹-THC were studied on the release and accumulation of ³H5HT and ³HNE in a rat forebrain synaptosomal preparation. These studies were designed to evaluate the possible sites of action of Δ⁹-THC on these two processes. Δ⁹-THC inhibited the accumulation of ³H-leucine, ³HNE, and ³H5HT, as well as facilitated the release of the latter two amines (to a lesser degree), but had no effect on the release of ³H-leucine. Eighteen-hour pre-treatment with reserpine diminished the ability of Δ⁹-THC to induce release of ³H5HT, but had no effect on the $\text{in vitro}$ inhibition of synaptosomal uptake of this amine. Concentrations of Δ⁹-THC which blocked the uptake of ³H5HT also reduced the conversion of ³H5HT to ³H-5-hydroxy-3-indoleacetic acid. However, Δ⁹-THC, at concentrations which facilitated release of ³H5HT from preloaded synaptosomes, increased the amount of ³H5HIAA found in the medium. Taken together, these data suggest that Δ⁹-THC facilitates release from the synaptic vesicle and retards accumulation at the neuronal membrane.     

Separate radioimmune measurements of body fluid Δ9-THC and 11-nor-9-carboxy-Δ9-THC

Simultaneous native molecule and discrete metabolite immune assays were performed after exposure of subjects to standardized Δ⁹-THC cigarettes. Plasma (and urine) 11-nor-9-carboxy-Δ⁹-THC remains elevated long after Δ⁹-THC becomes scant or undetectable enabling simple radioimmune determination of recent versus distant exposure to multiple cigarettes.     

Acquisition of tolerance to Δ-9-THC as measured by the response of a cellular function

The development of tolerance to delta-9-tetrahydrocannabinol (Δ-9-THC) was investigated by measuring respiration in brain tissue after acute or chronic administration. Mice were given either single or seven daily repeated intraperitoneal injections of 50 mg/Kg of delta-9-tetrahydrocannabinol (Δ-9-THC) or control vehicle. The final injection for all drug treated animals included radiolabeled ³H-Δ-9-THC. The mice were sacrificed at 1 hour, 2 hours, 4 hours, 24 hours, and 7 days after the final injection. Δ-9-THC depressed respiration, but after repeated injections was significantly less effective in this regard, indicating acquisition of tolerance to Δ-9-THC. Because the concentration of radiolabeled cannabinoids in brain tissue from each group is not appreciably different, a cellular as opposed to distributional mode of tolerance is suggested.     

Hydroxylation and glycosylation of Δ9-tetrahydrocannabinol by Catharanthus roseus cell suspension culture

Δ⁹-tetrahydrocannabinol is the active constituent in Cannabis sativa, with reported analgesic, anti-emetic, anti-oxidative, neuroprotective, and anti-inflammatory activities. Δ⁹-THC has been used to treat a number of disease states including pain, anxiety, asthma, glaucoma, and hypertension. Poor water solubility of Δ⁹-THC greatly reduces its clinical effectiveness. Consequently, there is a need to modify the compound to increase its polarity and pharmaceutical efficacy. The aim of this study was to test the capability of Catharanthus roseus suspension cultured cells to convert Δ⁹-THC into more polar derivatives. The transformed metabolites were analyzed and isolated by HPLC. Structures of some new derivatives were proposed on the basis of molecular ion peaks and fragmentation patterns obtained from LC-MS and UV spectra obtained by HPLC, respectively. Δ⁹-THC was rapidly absorbed by Catharanthus roseus cultured cells and upon biotransformation new glycosylated and hydroxylated derivatives were isolated by preparative HPLC. In addition, cannabinol was detected as degradation product, including its glycosylated derivative. Based on these results, it is concluded that Catharanthus cultured cells have great potential to transform Δ⁹-THC into more polar derivatives and can be used for the large scale production of new cannabinoids, which can be a source of new compounds with interesting pharmacological profiles.     

Inhibition of sea urchin fertilization by fatty acid ethanolamides and cannabinoids

The influence of saturated and unsaturated fatty acid ethanolamides as well as Δ⁹-tetrahydrocannabinol (Δ⁹-THC), WIN 55,212-2 and cannabinoid CB₁ receptor antagonist SR 141716 on sea urchin fertilization was studied. The ethanolamides of arachidonic, oleic and linoleic acids but not saturated fatty acid (C₁₄–C₂₀) derivatives inhibited fertilization when pre-incubated with sperm cells. Δ⁹-THC and WIN 55,212-2 also inhibited fertilization, Δ⁹-THC being ten times as potent as WIN 55,212-2. Selective cannabinoid CB₁ receptor antagonist SR 141716 also blocked fertilization and did not antagonize the action of Δ⁹-THC. The obtained results indicate that different unsaturated fatty acid ethanolamides may control sea urchin fertilization, and that sea urchin sperm cell cannabinoid receptor may differ from the known cannabinoid receptor subtypes.     

Δ-Tetrahydrocannabinol regulates the p53 post-translational modifiers Murine double minute 2 and the Small Ubiquitin MOdifier protein in the rat brain

The phytocannabinoid Δ⁹-Tetrahydrocannabinol (Δ⁹-THC), the main psychoactive cannabinoid in cannabis, activates a number of signalling cascades including p53. This study examines the role of Δ⁹-THC in regulating the p53 post-translational modifier proteins, Murine double minute (Mdm2) and Small Ubquitin-like MOdifier protein 1 (SUMO-1) in cortical neurons. Δ⁹-THC increased both Mdm2 and SUMO-1 protein expression and induced the deSUMOylation of p53 in a cannabinoid receptor type 1 (CB₁)-receptor dependent manner. We demonstrate that Δ⁹-THC decreased the SUMOylation of the CB₁ receptor. The data reveal a novel role for cannabinoid receptor activation in modulating the SUMO regulatory system.

Structured summary

MINT-7266621: Cb1 (uniprotkb:P20272) physically interacts (MI:0915) with SUMO-1 (uniprotkb:Q5I0H3) by anti bait coimmunoprecipitation(MI:0006)MINT-7266633: SUMO-1 (uniprotkb:Q5I0H3) and Cb1 (uniprotkb:P20272) colocalize (MI:0403) by fluorescence microscopy (MI:0416)MINT-7266611: p53 (uniprotkb:P10361) physically interacts (MI:0915) with SUMO-1 (uniprotkb:Q5I0H3) by anti bait coimmunoprecipitation (MI:0006)     

Chronic ethanol administration decreases fatty acyl-CoA desaturase activities in rat liver microsomes

The Δ⁹-desaturase system in liver microsome from rats treated chronically with ethanol was studied. Stearoyl-CoA desaturase activity decreased by 80% and palmitoyl-CoA desaturase activity was not detectable in microsomes from ethanol-fed rats, while activities of electron transport components such as NADH-cytochrome c and NADH-ferricyanide reductases remained unchanged. However, chronic ethanol administration resulted in an adaptive induction of the activity of NADPH-cytochrome c reductase and the contents of cytochrome b₅ and P-450. The activity of the terminal component (cyanide-sensitive factor; CSF) of the desaturase system was greatly depressed by ethanol treatment. The NADH/NAD ratio in microsomes of ethanol-fed rats increased over 2-fold. These results suggest that, during chronic ethanol ingestion, decreased activities of Δ⁹-desaturases are due mainly to a decreased content of the terminal component of the desaturase system.     

Prognostic value of cortically induced motor evoked activity by TMS in chronic stroke: Caveats from a revealing single clinical case

Background

We report the case of a chronic stroke patient (62?months after injury) showing total absence of motor activity evoked by transcranial magnetic stimulation (TMS) of spared regions of the left motor cortex, but near-to-complete recovery of motor abilities in the affected hand.

Case presentation

Multimodal investigations included detailed TMS based motor mapping, motor evoked potentials (MEP), and Cortical Silent period (CSP) as well as functional magnetic resonance imaging (fMRI) of motor activity, MRI based lesion analysis and Diffusion Tensor Imaging (DTI) Tractography of corticospinal tract (CST). Anatomical analysis revealed a left hemisphere subinsular lesion interrupting the descending left CST at the level of the internal capsule. The absence of MEPs after intense TMS pulses to the ipsilesional M1, and the reversible suppression of ongoing electromyographic (EMG) activity (indexed by CSP) demonstrate a weak modulation of subcortical systems by the ipsilesional left frontal cortex, but an inability to induce efficient descending volleys from those cortical locations to right hand and forearm muscles. Functional MRI recordings under grasping and finger tapping patterns involving the affected hand showed slight signs of subcortical recruitment, as compared to the unaffected hand and hemisphere, as well as the expected cortical activations.

Conclusions

The potential sources of motor voluntary activity for the affected hand in absence of MEPs are discussed. We conclude that multimodal analysis may contribute to a more accurate prognosis of stroke patients.     

Effects of delta9-tetrahydrocannabinol on ATPases in mouse brain subcellular fractions.

The effect of (?)-Δ⁹-THC on the activities of Mg²⁺?, Na⁺?K⁺? and Mg²⁺Ca²⁺-ATPases were studied in mouse brain subcellular fractions. $\text{In vitro}$treatment with Δ⁹-THC produced a dose dependent stimulation of Mg²⁺ ATPase in the crude mitochondrial fraction and its subfractions and a dose-related inhibition of this activity in the microsomal fraction. Na⁺-K⁺- and Mg²⁺-Ca²⁺-ATPase activities were inhibited in a dose-related manner in all subcellular fractions studied.     

Further evidence for a role of 2-phenylethylamine in the mode of action of delta 9-tetrahydrocannabinol

In rabbits, Δ⁹-tetrahydrocannabinol (Δ⁹-THC) increased the recovery of labeled 2-phenylethylamine (PEA) from brain following its intraventricular administration. Δ⁹-THC also enhanced the excitatory effect of iontophoretic PEA on cortical unit potentials. Although Δ⁹-THC induced sedation in mice, the subsequent injection of reserpine induced transient excitement. Low doses of PEA, which do not significantly alter the behavior of mice, induced marked excitement in mice pretreated with Δ⁹-THC. In mice treated with pargyline, Δ⁹-THC induced excitement (instead of sedation); this excitement was increased by PEA and reduced by phenylethanolamine. These results suggest that Δ⁹-THC inhibits the disposition of PEA. Since endogenous PEA may be one of the adrenergic ergotropic modulators, it may play a role in the euphoriant effect of marihuana.     

Long-range temporal correlations in the EEG bursts of human preterm babies

The electrical activity in the very early human preterm brain, as recorded by scalp EEG, is mostly discontinuous and has bursts of high-frequency oscillatory activity nested within slow-wave depolarisations of high amplitude. The temporal organisation of the occurrence of these EEG bursts has not been previously investigated. We analysed the distribution of the EEG bursts in 11 very preterm (23-30 weeks gestational age) human babies through two estimates of the Hurst exponent. We found long-range temporal correlations (LRTCs) in the occurrence of these EEG bursts demonstrating that even in the very immature human brain, when the cerebral cortical structure is far from fully developed, there is non-trivial temporal structuring of electrical activity.     

Spectral and coherence EEG analysis of rats differing in the level of seizure readiness

The resting EEGs of several brain structures (motor and visual cortex, caudate nucleus and intralaminar thalamic nuclei) were submitted to spectral and coherence computer analyses in two rat strains. Genetically predisposed to convulsive state KM rats were shown to differ from nonpredisposed Wistar rats in EEG spectral properties. KM rats EEG pattern was characterized by increase of low frequencies (1-2 Hz) power and decrease of faster activity (5-12 Hz) power in cortical spectrograms as well as by decrease of caudate nucleus EEG absolute power. The coherence value between cortical or subcortical structures at below 4 Hz was intensified in KM rats. Reinforcement of cortical auto-oscillating properties manifested by ECoG synchronization in cortical-thalamic resonance interaction as well as weakening of striatal inhibitory system may constitute neurophysiological mechanisms of enhanced convulsive readiness. The probable role of mediator imbalance in these mechanisms is discussed.     

Distinct pharmacology and metabolism of K2 synthetic cannabinoids compared to Δ-THC: Mechanism underlying greater toxicity?

K2 or Spice products are emerging drugs of abuse that contain synthetic cannabinoids (SCBs). Although assumed by many teens and first time drug users to be a “safe” and “legal” alternative to marijuana, many recent reports indicate that SCBs present in K2 produce toxicity not associated with the primary psychoactive component of marijuana, ?⁹-tetrahydrocannabinol (Δ⁹-THC). This mini-review will summarize recent evidence that use of K2 products poses greater health risks relative to marijuana, and suggest that distinct pharmacological properties and metabolism of SCBs relative to Δ⁹-THC may contribute to the observed toxicity. Studies reviewed will indicate that in contrast to partial agonist properties of Δ⁹-THC typically observed in vitro, SCBs in K2 products act as full cannabinoid receptor type 1 (CB1R) and type 2 (CB2R) agonists in both cellular assays and animal studies. Furthermore, unlike Δ⁹-THC metabolism, several SCB metabolites retain high affinity for, and exhibit a range of intrinsic activities at, CB1 and CB2Rs. Finally, several reports indicate that although quasi-legal SCBs initially evaded detection and legal consequences, these presumed “advantages” have been limited by new legislation and development of product and human testing capabilities. Collectively, evidence reported in this mini-review suggests that K2 products are neither safe nor legal alternatives to marijuana. Instead, enhanced toxicity of K2 products relative to marijuana, perhaps resulting from the combined actions of a complex mixture of different SCBs present and their active metabolites that retain high affinity for CB1 and CB2Rs, highlights the inherent danger that may accompany use of these substances.     

Effect of Delta-9-Tetrahydrocannabinol on Mouse Resistance to Systemic Candida albicans Infection

Delta-9-tetrahydrocannabinol (Δ⁹-THC), the psychoactive component of marijuana, is known to suppress the immune responses to bacterial, viral and protozoan infections, but its effects on fungal infections have not been studied. Therefore, we investigated the effects of chronic Δ⁹-THC treatment on mouse resistance to systemic Candida albicans (C. albicans) infection. To determine the outcome of chronic Δ⁹-THC treatment on primary, acute systemic candidiasis, c57BL/6 mice were given vehicle or Δ⁹-THC (16 mg/kg) in vehicle on days 1–4, 8–11 and 15–18. On day 19, mice were infected with 5×10⁵ C. albicans. We also determined the effect of chronic Δ⁹-THC (4–64 mg/kg) treatment on mice infected with a non-lethal dose of 7.5×10⁴ C. albicans on day 2, followed by a higher challenge with 5×10⁵ C. albicans on day 19. Mouse resistance to the infection was assessed by survival and tissue fungal load. Serum cytokine levels were determine to evaluate the immune responses. In the acute infection, chronic Δ⁹-THC treatment had no effect on mouse survival or tissue fungal load when compared to vehicle treated mice. However, Δ⁹-THC significantly suppressed IL-12p70 and IL-12p40 as well as marginally suppressed IL-17 versus vehicle treated mice. In comparison, when mice were given a secondary yeast infection, Δ⁹-THC significantly decreased survival, increased tissue fungal burden and suppressed serum IFN-γ and IL-12p40 levels compared to vehicle treated mice. The data showed that chronic Δ⁹-THC treatment decreased the efficacy of the memory immune response to candida infection, which correlated with a decrease in IFN-γ that was only observed after the secondary candida challenge.     

EFFECT OF DELTA-9-TETRAHYDROCANNABINOL ADMINISTRATION ON THE LIPID CONSTITUENTS OF RAT BRAIN SUBCELLULAR FRACTIONS

An investigation on the effects of acute (10 mg/kg) and chronic (10 mg/kg for 15 days) treatment with Δ⁹-THC administration by the intraperitoneal route, on the cholesterol, cerebroside and individual phospholipid contents in microsomal, synaptosomal, mitochodrial and myelin fractions from adult rat brain, is reported. The drug has been found to affect the different subcellular membranous lipid and phospholipid components in a characteristic manner.