Activity of THC, CBD, and CBN on Human ACE2 and SARS-CoV1/2 Main Protease to Understand Antiviral Defense Mechanism.

THC, CBD, and CBN were reported as promising candidates against SARS-CoV2 infection, but the mechanism of action of these three cannabinoids is not understood. This study aims to determine the mechanism of action of THC, CBD, and CBN by selecting two essential targets that directly affect the coronavirus infections as viral main proteases and human angiotensin-converting enzyme2. Tested THC and CBD presented a dual-action action against both selected targets. Only CBD acted as a potent viral main protease inhibitor at the IC50 value of 1.86 ± 0.04 µM and exhibited only moderate activity against human angiotensin-converting enzyme2 at the IC50 value of 14.65 ± 0.47 µM. THC acted as a moderate inhibitor against both viral main protease and human angiotensin-converting enzymes2 at the IC50 value of 16.23 ± 1.71 µM and 11.47 ± 3.60 µM, respectively. Here, we discuss cannabinoid-associated antiviral activity mechanisms based on in silico docking studies and in vitro receptor binding studies.

Antinociceptive and Immune Effects of Delta-9-Tetrahydrocannabinol or Cannabidiol in Male Versus Female Rats with Persistent Inflammatory Pain.

Chronic pain is the most common reason reported for using medical cannabis. The goal of this research was to determine whether the two primary phytocannabinoids, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), are effective treatments for persistent inflammatory pain. In experiment 1, inflammation was induced by intraplantar injection of Complete Freund's adjuvant (CFA). Then THC (0.0-4.0 mg/kg, i.p.) or CBD (0.0-10 mg/kg, i.p.) was administered twice daily for 3 days. On day 4, THC, CBD, or vehicle was administered, and allodynia, hyperalgesia, weight-bearing, locomotor activity, and hindpaw edema were assessed 0.5-4 hours postinjection. In experiment 2, CFA or mineral oil (no-pain control)-treated rats were given THC (2.0 mg/kg, i.p.), CBD (10 mg/kg, i.p.), or vehicle in the same manner as in experiment 1. Four hours postinjection on day 4, serum samples were taken for analysis of cytokines known to influence inflammatory pain: interleukin (IL)-1ß, IL-6, IL-10, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α THC dose-dependently reduced pain-related behaviors but did not reduce hindpaw edema, and little tolerance developed to THC's effects. In contrast, CBD effects on inflammatory pain were minimal. THC produced little to no change in serum cytokines, whereas CBD decreased IL-1ß, IL-10, and IFN-γ and increased IL-6. Few sex differences in antinociception or immune modulation were observed with either drug, but CFA-induced immune activation was significantly greater in males than females. These results suggest that THC may be more beneficial than CBD for reducing inflammatory pain in that THC maintains its efficacy with short-term treatment in both sexes and does not induce immune activation. SIGNIFICANCE STATEMENT: The pain-relieving effects of cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) are examined in male and female rats with persistent inflammatory pain to determine whether individual phytocannabinoids could be a viable treatment for men and women with chronic inflammatory pain. Additionally, sex differences in the immune response to an adjuvant and to THC and CBD are characterized to provide preliminary insight into immune-related effects of cannabinoid-based therapy for pain.

Cannabidiol, cannabinol and their combinations act as peripheral analgesics in a rat model of myofascial pain.

OBJECTIVE: This study investigated whether local intramuscular injection of non-psychoactive cannabinoids, cannabidiol (CBD), cannabinol (CBN), cannabichromene (CBC) and their combinations can decrease nerve growth factor (NGF)-induced masticatory muscle sensitization in female rats. DESIGN: In awake rats, changes in mechanical sensitivity induced by intramuscular injection of NGF and cannabinoids were measured by applying an electronic von Frey hair over the masseter muscle to measure the withdrawal response. The effect of CBD (5 mg/ml) and CBN (1 mg/ml) or their combinations CBD/CBN (1:1 mg/ml or 5:1 mg/ml) were assessed. To confirm a peripheral action, electrophysiological experiments were undertaken in anesthetized rats to examine whether intramuscular injections of CBD (5 mg/ml) and CBN (1 mg/ml) altered the mechanical threshold of masticatory muscle mechanoreceptors. RESULTS: In behavioral experiments, CBD (5 mg/ml) or CBN (1 mg/ml) decreased NGF-induced mechanical sensitization. Combinations of CBD/CBN induced a longer-lasting reduction of mechanical sensitization than either compound alone. No significant change in mechanical withdrawal threshold was observed in the contralateral masseter muscles and no impairment of motor function was found with the inverted screen test after any of the treatments. Consistent with behavioral results, CBD (5 mg/ml), CBN (1 mg/ml) and the combination of CBD/CBN (1:1 mg/ml) increased the mechanical threshold of masseter muscle mechanoreceptors. However, combining CBD/CBN (5:1 mg/ml) at a higher ratio reduced the duration of this effect. This may indicate an inhibitory effect of higher concentrations of CBD on CBN. CONCLUSIONS: These results suggest that peripheral application of these non-psychoactive cannabinoids may provide analgesic relief for chronic muscle pain disorders such as temporomandibular disorders and fibromyalgia without central side 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.

Acute effects of Delta9-tetrahydrocannabinol and standardized cannabis extract on the auditory evoked mismatch negativity.

Reduced amplitudes of auditory evoked mismatch negativity (MMN) have often been found in schizophrenic patients, indicating deficient auditory information processing and working memory. Cannabis-induced psychotic states may resemble schizophrenia. Currently, there are discussions focusing on the close relationship between cannabis, the endocannabinoid and dopaminergic system, and the onset of schizophrenic psychosis. This study investigated the effects of cannabis on MMN amplitude in 22 healthy volunteers (age 28+/-6 years, 11 male) by comparing Delta(9)-tetrahydrocannabinol (Delta(9)-THC) and standardized cannabis extract containing Delta(9)-THC and cannabidiol (CBD) in a prospective, double-blind, placebo-controlled cross-over design. The MMNs resulting from 1000 auditory stimuli were recorded by 32 channel EEG. The standard stimuli were 1000 Hz, 80 dB SPL, and 100 ms duration. The deviant stimuli differed in frequency (1500 Hz). Significantly greater MMN amplitude values at central electrodes were found under cannabis extract, but not under Delta(9)-THC. There were no significant differences between MMN amplitudes at frontal electrodes. MMN amplitudes at central electrodes were significantly correlated with 11-OH-THC concentration, the most important psychoactive metabolite of Delta(9)-THC. Since the main difference between Delta(9)-THC and standardized cannabis extract is CBD, which seems to have neuroprotective and anti-psychotic properties, it can be speculated whether the greater MMN amplitude that may imply higher cortical activation and cognitive performance is related to the positive effects of CBD. This effect may be relevant for auditory cortex activity in particular because only MMN amplitudes at the central, but not at the frontal electrodes were enhanced under cannabis.

Cannabinoid CB1-receptor mediated regulation of gastrointestinal motility in mice in a model of intestinal inflammation.

1. We have studied the effect of cannabinoid agonists (CP 55,940 and cannabinol) on intestinal motility in a model of intestinal inflammation (induced by oral croton oil in mice) and measured cannabinoid receptor expression, endocannabinoids (anandamide and 2-arachidonylglycerol) and anandamide amidohydrolase activity both in physiological and pathophysiological states. 2. CP 55,940 (0.03 - 10 nmol mouse(-1)) and cannabinol (10 - 3000 nmol mouse(-1)) were more active in delaying intestinal motility in croton oil-treated mice than in control mice. These inhibitory effects were counteracted by the selective cannabinoid CB(1) receptor antagonist SR141716A (16 nmol mouse(-1)). SR141716A (1 - 300 nmol mouse(-1)), administered alone, increased intestinal motility to the same extent in both control and croton oil-treated mice. 3. Croton oil-induced intestinal inflammation was associated with an increased expression of CB(1) receptor, an unprecedented example of up-regulation of cannabinoid receptors during inflammation. 4. High levels of anandamide and 2-arachidonylglycerol were detected in the small intestine, although no differences were observed between control and croton oil-treated mice; by contrast anandamide amidohydrolase activity increased 2 fold in the inflamed small intestine. 5. It is concluded that inflammation of the gut increases the potency of cannabinoid agonists possibly by 'up-regulating' CB(1) receptor expression; in addition, endocannabinoids, whose turnover is increased in inflamed gut, might tonically inhibit intestinal motility.

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.