Inhibition of human recombinant T‐type calcium channels by phytocannabinoids in vitro

Mirlohi, Somayeh; Bladen, Chris; Santiago, Marina; Arnold, Jonathon C.; McGregor, Ian; Connor, Mark

doi:10.1111/bph.15842

Cited by 16 publications

(16 citation statements)

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“…Our findings that the minor phytocannabinoids CBDVA and CBGVA inhibit T-type calcium channels extend upon research showing that phytocannabinoids and synthetic cannabinoids inhibit these channels ( Ross et al, 2008 ; Mirlohi et al, 2021 , 2022 ). We recently reported that the structurally related phytocannabinoid CBGA, which is also anticonvulsant, inhibited Ca v 3.1 and Ca v 3.2 channels ( Mirlohi et al, 2022 ). Here CBDVA and CBGVA displayed lower potency than CBGA using an identical fluorescent reporter assay.…”

Section: Discussionsupporting

confidence: 82%

“…Whereas in this study, CBGVA negatively shifted fast inactivation but not activation, and CBDVA did not affect either state. The preferential shift of the fast inactivation curve in Ca v 3.1 channels by CBGVA is similar to CBD, CBG and CBDV at Ca v 3.1 channels (Ross et al, 2008;Mirlohi et al, 2022). Hyperpolarising shifts of steady-state fast inactivation suggest preferential binding of CBGVA to the inactivated state Frontiers in Pharmacology frontiersin.org of the Ca v 3.1 channels (Freeze et al, 2006;Eckle and Todorovic, 2010).…”

Section: Cbgva and Cbdva Inhibition Of Ca V 31 Is Frequency-dependentmentioning

confidence: 67%

“…Human embryonic kidney 293 (HEK) Flp-In T-REx cells stably expressing T-type Ca v 3.1, Ca v 3.2, or Ca v 3.3 channels were used ( Bladen et al, 2021 ; Mirlohi et al, 2022 ). HEK 293 GPR55 cells were generously provided by Dr Julia Kargl (University of Graz, AUT) ( Kargl et al, 2012 ).…”

Section: Methodsmentioning

confidence: 99%

“…There exists a paucity of data on the molecular pharmacology of these acidic phytocannabinoids, particularly at epilepsy-relevant CNS drug targets. We have recently reported that phytocannabinoids Δ 9 -tetrahydrocannabinolic acid (THCA) and CBGA inhibited the voltage-gated T-type calcium (Ca v 3) channels ( Mirlohi et al, 2021 , 2022 ). Ca v 3 channels, which comprise three subtypes, Ca v 3.1, Ca v 3.2, and Ca v 3.3, are expressed in neuronal cells where they are activated by small membrane depolarisations and are considered neuronal pacemakers ( Cribbs et al, 1998 ) Dysfunction of Ca v 3 channels is associated with various medical conditions, including epilepsy, sleep disturbances and pain ( Bourinet et al, 2005 ; Tringham et al, 2012 ).…”

Section: Introductionmentioning

confidence: 99%

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The anticonvulsant phytocannabinoids CBGVA and CBDVA inhibit recombinant T-type channels

et al. 2022

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Introduction: Cannabidiol (CBD) has been clinically approved for intractable epilepsies, offering hope that novel anticonvulsants in the phytocannabinoid class might be developed. Looking beyond CBD, we have recently reported that a series of biosynthetic precursor molecules found in cannabis display anticonvulsant properties. However, information on the pharmacological activities of these compounds on CNS drug targets is limited. The current study aimed to fill this knowledge gap by investigating whether anticonvulsant phytocannabinoids affect T-type calcium channels, which are known to modulate neuronal excitability, and may be relevant to the anti-seizure effects of this class of compounds.Materials and methods: A fluorescence-based assay was used to screen the ability of the phytocannabinoids to inhibit human T-type calcium channels overexpressed in HEK-293 cells. A subset of compounds was further examined using patch-clamp electrophysiology. Alphascreen technology was used to characterise selected compounds against G-protein coupled-receptor 55 (GPR55) overexpressed in HEK-293 cells, as GPR55 is another target of the phytocannabinoids.Results: A single 10 µM concentration screen in the fluorescence-based assay showed that phytocannabinoids inhibited T-type channels with substantial effects on Cav3.1 and Cav3.2 channels compared to the Cav3.3 channel. The anticonvulsant phytocannabinoids cannabigerovarinic acid (CBGVA) and cannabidivarinic acid (CBDVA) had the greatest magnitudes of effect (≥80% inhibition against Cav3.1 and Cav3.2), so were fully characterized in concentration-response studies. CBGVA and CBDVA had IC50 values of 6 μM and 2 µM on Cav3.1 channels; 2 μM and 11 µM on Cav3.2 channels, respectively. Biophysical studies at Cav3.1 showed that CBGVA caused a hyperpolarisation shift of steady-state inhibition. Both CBGVA and CBDVA had a use-dependent effect and preferentially inhibited Cav3.1 current in a slow inactivated state. CBGVA and CBDVA were also shown to antagonise GPR55.Conclusion and implications: These findings show that CBGVA and CBDVA inhibit T-type calcium channels and GPR55. These compounds should be further investigated to develop novel therapeutics for treating diseases associated with dysfunctional T-type channel activity.

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Section: Discussionsupporting

confidence: 82%

Section: Cbgva and Cbdva Inhibition Of Ca V 31 Is Frequency-dependentmentioning

confidence: 67%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The anticonvulsant phytocannabinoids CBGVA and CBDVA inhibit recombinant T-type channels

et al. 2022

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“…Since CBD does not activate CB1 and CB2 receptors, some of the attention in cannabinoid research has recently been focused on CB1 and CB2-independent cellular and molecular targets for CBD and other phytocannabinoids such as cannabigerol and cannabidivarin ( Ghovanloo et al, 2022 ; Isaev et al, 2022 ; Mirlohi et al, 2022 ). In fact, in earlier studies, cannabinoid-receptor independent effects have been described for both endogenous and synthetic cannabinoids as well ( Johnson et al, 1993 ; Fan, 1995 ; Oz et al, 2000 ).…”

Section: Introductionmentioning

confidence: 99%

Effects of cannabinoids on ligand-gated ion channels

2022

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Phytocannabinoids such as Δ9-tetrahydrocannabinol and cannabidiol, endocannabinoids such as N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol, and synthetic cannabinoids such as CP47,497 and JWH-018 constitute major groups of structurally diverse cannabinoids. Along with these cannabinoids, CB1 and CB2 cannabinoid receptors and enzymes involved in synthesis and degradation of endocannabinoids comprise the major components of the cannabinoid system. Although, cannabinoid receptors are known to be involved in anti-convulsant, anti-nociceptive, anti-psychotic, anti-emetic, and anti-oxidant effects of cannabinoids, in recent years, an increasing number of studies suggest that, at pharmacologically relevant concentrations, these compounds interact with several molecular targets including G-protein coupled receptors, ion channels, and enzymes in a cannabinoid-receptor independent manner. In this report, the direct actions of endo-, phyto-, and synthetic cannabinoids on the functional properties of ligand-gated ion channels and the plausible mechanisms mediating these effects were reviewed and discussed.

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Effects of cannabidiol and other phytocannabinoids on voltage- and ligand-gated ion channels

Öz

Yang

Mahgoub

et al. 2023

Cannabis Use, Neurobiology, Psychology, and Treatment

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Inhibition of human recombinant T‐type calcium channels by phytocannabinoids in vitro

Cited by 16 publications

References 61 publications

The anticonvulsant phytocannabinoids CBGVA and CBDVA inhibit recombinant T-type channels

The anticonvulsant phytocannabinoids CBGVA and CBDVA inhibit recombinant T-type channels

Effects of cannabinoids on ligand-gated ion channels

Effects of cannabidiol and other phytocannabinoids on voltage- and ligand-gated ion channels

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