CBG May Amplify Adenosine Signaling Through A3 Receptors

Cannabigerol is frequently introduced as the “mother cannabinoid” because its acidic precursor helps the cannabis plant produce several better-known cannabinoids. That description explains where CBG comes from, but it says very little about what the compound may actually do inside the body.

A new laboratory study published in Pharmacological Research¹ points toward a more useful possibility. Researchers found that CBG and cannabidiol can influence the human adenosine A3 receptor, a cellular receptor involved in inflammation, pain signalling, immune activity, and responses to tissue stress. CBG produced the stronger effect, making cells dramatically more responsive to adenosine under the conditions tested.

This does not mean CBG has been proven to relieve pain, suppress inflammation, or protect human tissue. The experiments used engineered cells and computer simulations rather than patients or consumer products. What they provide is a plausible new mechanism that could help explain why CBG produces different effects across biological settings.

What Adenosine Does in the Body

Adenosine is a naturally occurring molecule used throughout the body. It helps regulate neural activity, blood flow, immune responses, metabolism, and the way tissues react to stress. Its local concentration can rise during inflammation, oxygen deprivation, injury, and intense cellular activity.

Adenosine sends signals through four receptor families called A1, A2A, A2B, and A3. Each receptor can produce different effects depending on the tissue, surrounding chemistry, and health condition. The A3 receptor is less thoroughly characterized than some of its relatives, but it has attracted interest as a potential target in inflammatory disease, chronic pain, ischemic injury, and cancer research. The US National Institute of Diabetes and Digestive and Kidney Diseases has even described positive allosteric modulators of the A3 receptor as potential research tools for several therapeutic areas.

That broader context matters. Cannabinoids are commonly discussed through the endocannabinoid system, especially CB1 and CB2 receptors. However, CBD and CBG are pharmacologically active at multiple targets. Recent research covered by MyCannabis has examined CBG and inflammatory activity in rheumatoid arthritis models, while other work has explored its effects on serotonin, adrenergic, and transient receptor potential pathways. The new study adds the A3 receptor to that expanding map.

CBG Appeared to Amplify an Existing Signal

The researchers used Chinese hamster ovary cells engineered to express the human A3 receptor. They measured cyclic adenosine monophosphate, or cAMP, a messenger molecule that changes when the receptor activates its associated signalling pathway.

CBD and CBG both reduced forskolin-stimulated cAMP accumulation. The effect disappeared in cells without the human A3 receptor and was blocked by PSB-10, a selective A3 receptor antagonist. An A2A receptor antagonist did not block it. Together, those controls support the conclusion that the observed response depended on A3 receptor activity in this experimental system.

CBG was more potent than CBD. Its half-maximal inhibitory concentration was 0.130 micromolar, compared with 1.05 micromolar for CBD. CBG was therefore roughly eight times more potent by this measure, although both cannabinoids achieved broadly comparable maximum responses when tested alone.

The most striking result appeared when CBG was combined with adenosine. Adding 100 nanomolar CBG reduced the apparent concentration of adenosine needed for a half-maximal response from 138 nanomolar to 1 nanomolar. That corresponds to an approximately 138-fold increase in apparent adenosine potency. CBG also increased the maximum inhibitory response from 60% to 83%.

CBD shifted the adenosine response too, but more modestly. It lowered the apparent IC50 to 42 nanomolar while reducing the maximum response to 50%. That contrast suggests CBD and CBG should not be treated as interchangeable simply because neither is intoxicating.

Why the Signal Amplifier Analogy Matters

A conventional receptor agonist can be imagined as a key that activates a lock. The CBG results point toward something more context dependent. CBG may activate the A3 receptor under one condition while changing how the receptor responds to adenosine when the natural signalling molecule is already present.

Computer docking and molecular dynamics simulations offered a possible explanation. Without adenosine, CBD and CBG were predicted to occupy the receptor’s primary binding region. When adenosine occupied that site, CBG maintained a stable secondary position in all simulation replicas. The researchers propose that this secondary pose may subtly reorganize the contacts between adenosine and the receptor, improving the signal rather than simply replacing adenosine.

In practical terms, CBG may behave less like an independent on-off switch and more like an amplifier whose effect depends on the signal already present. That concept could help explain why cannabinoid effects vary with tissue type, inflammation, receptor abundance, and physiological stress. It also challenges the expectation that one cannabinoid should produce one consistent effect everywhere in the body.

This multi-target character is already visible elsewhere in the evidence. A recent MyCannabis report on CBG’s antipsychotic-like effects in mice highlighted adrenergic and serotonin-related mechanisms. Research into cannabinoid combinations likewise shows how outcomes may emerge from interactions among several compounds and signalling systems rather than a single receptor pathway.

Could This Translate Into Better Health?

Possibly, but that conclusion is several steps beyond the evidence. A3 receptor signalling has been investigated in connection with inflammation, persistent pain, immune regulation, tissue protection, and disease-associated remodelling. A review of A3 receptor-mediated pain control describes encouraging preclinical findings, particularly for neuropathic and inflammatory pain. CBG’s ability to enhance adenosine signalling could eventually prove relevant to some of those processes.

The findings suggest several research possibilities:

• Developing CBG-derived compounds that modulate A3 signalling more selectively
• Testing whether the mechanism operates in native human cells and tissues
• Exploring whether local adenosine levels predict when CBG has an effect
• Investigating inflammation, pain, and tissue injury without assuming one universal outcome

None of these possibilities establishes that a CBG oil, edible, flower, or other retail product will produce a therapeutic response. A receptor-level effect can disappear during digestion, metabolism, distribution, or elimination. The relevant concentration may never reach the target tissue. Other cannabinoids and plant compounds may strengthen, weaken, or alter the effect.

The A3 receptor is also not a universal health switch. Increasing its activity could be useful in one tissue or disease state and unhelpful in another. Adenosine biology changes with inflammation, oxygen availability, receptor density, and the expression of other receptor subtypes. This is why a 138-fold laboratory shift, although scientifically notable, cannot be converted into a consumer dose or a claim that CBG is 138 times more effective at anything in people.

Important Limits of the Research

The study measured a downstream cAMP response rather than direct G-protein engagement. CBD and CBG were each tested at only one concentration in the adenosine-combination experiments, preventing a full quantitative analysis of their modulatory behaviour.

The researchers also did not directly demonstrate where either cannabinoid binds. The proposed secondary CBG position came from computational modelling. It is a credible, testable explanation, but not structural proof. Complete comparisons across A1, A2A, A2B, and A3 receptors were not performed, so receptor selectivity remains unresolved.

Most importantly, engineered ovary cells do not reproduce the complexity of a human nervous, cardiovascular, or immune system. The experiments used purified cannabinoids, not CBG-rich cannabis extracts, and did not determine whether physiologically attainable concentrations could reproduce the response. Recent pharmacokinetic research continues to underscore how much remains unknown about how CBG moves through and affects living organisms.

CBG Research Is Moving Beyond Simple Labels

The study’s real contribution is not proof of a new CBG treatment. It is a stronger framework for asking why CBG may behave differently across biological environments. If CBG can respond to the occupancy state of a receptor and reshape the action of an endogenous molecule, its pharmacology cannot be understood solely by listing the receptors it activates.

Future research will need direct binding experiments, measurements of early receptor signalling, comparisons across all adenosine receptor subtypes, and studies in native tissues and animals. Eventually, controlled human trials would be needed to connect the mechanism to symptoms or clinical outcomes.

For the average person, the responsible conclusion is straightforward: CBG may interact with a health-relevant signalling system in a more sophisticated way than previously recognized, but the study does not show that taking CBG improves health. It gives scientists a promising mechanism to test, not consumers a proven therapy.

References:

¹ Serrano-Marín, J., Navarro, G., Sánchez de Medina, V., Ferreiro-Vera, C., Lillo, J., & Franco, R. (2026). Cannabinoids as context-dependent modulators of the adenosine A3 receptors: Potential orthosteric and allosteric mechanisms. Pharmacological Research, 109641. https://doi.org/10.1016/j.phrs.2026.109641