Comprehensive Review of Cannabinoid Pharmacology, Receptor Systems, and Therapeutic Applications | Research

The takeaway

This broad review covers 15 years of cannabinoid receptor research, cataloging therapeutic properties including pain relief, muscle relaxation, anti-inflammation, appetite stimulation, and neuroprotection, while noting emerging research into CB receptor antagonists for obesity and addiction.

Read this if you want a thorough overview of what the endocannabinoid system does throughout the body and where therapeutic applications were heading in 2005.

Cannabinoid receptors distributed across CNS, immune, reproductive, GI, cardiovascular, and endocrine systems

What the researchers found

This comprehensive review covered 15 years of research since the discovery of the endocannabinoid system. It detailed two G-protein coupled cannabinoid receptors (CB1 and CB2), endocannabinoids produced "on demand" from membrane lipids, and the distribution of cannabinoid receptors across the central nervous system and peripheral tissues including immune, reproductive, gastrointestinal, cardiovascular, and endocrine systems.

Therapeutic properties of CB receptor agonists identified include analgesia, muscle relaxation, immunosuppression, anti-inflammation, antiallergic effects, mood improvement, appetite stimulation, antiemesis, lowered intraocular pressure, bronchodilation, neuroprotection, and antineoplastic effects.

Clinical research at the time focused on chronic pain and neurological disorders. CB receptor antagonists were under investigation for obesity and nicotine addiction, with additional potential proposed for alcohol and heroin dependency, schizophrenia, Parkinson's disease, and Alzheimer's disease.

Why it matters

This review provides one of the most complete snapshots of cannabinoid pharmacology as of 2005, documenting the remarkable breadth of biological processes influenced by the endocannabinoid system. The fact that both agonists and antagonists show therapeutic potential highlights the complexity of this signaling system.

The numbers in context

Two receptor subtypes: CB1 and CB2. Main endocannabinoids: anandamide and 2-AG. Receptors found in: CNS, immune system, reproductive tract, GI tract, sympathetic ganglia, endocrine glands, arteries, lung, heart. Therapeutic properties cataloged: 12+ distinct actions.

How the study worked

Comprehensive narrative review covering 15 years of research on the endocannabinoid system, cannabinoid receptors, endogenous ligands, synthetic modulators, and therapeutic applications. Covered pharmacology, receptor distribution, and both agonist and antagonist therapeutic potential.

What this study cannot tell us

As a narrative review, it does not systematically evaluate the quality of evidence for each therapeutic application. Many therapeutic claims were based on preclinical data. The rapid pace of research means some conclusions were quickly superseded.

How to read the evidence

Comprehensive narrative review from a leading cannabinoid researcher. Provides an authoritative overview but includes preclinical and clinical evidence without systematic quality assessment.

When this study was published

Published in 2005 by Franjo Grotenhermen, a prominent cannabinoid researcher. Many therapeutic applications discussed have since been tested in clinical trials.

The bigger picture

The breadth of cannabinoid receptor distribution across the body explains why cannabis affects so many different systems. This review captures a pivotal moment when research was expanding from understanding basic pharmacology toward developing targeted therapeutics for specific conditions.

Questions still open

Which of the many identified therapeutic properties will prove clinically useful in humans? Can CB receptor antagonists succeed as treatments for obesity and addiction?

Common questions

Why does cannabis affect so many different body systems?

Cannabinoid receptors are distributed throughout the body, not just in the brain. They are found in the immune system, digestive tract, heart, lungs, reproductive system, and endocrine glands, which is why cannabis use can affect such a wide range of body functions.

Can cannabinoid receptor blockers treat obesity?

As of this 2005 review, CB receptor antagonists were under investigation for obesity treatment. The concept was that blocking cannabinoid receptors involved in appetite stimulation could reduce food intake. Rimonabant was later approved but withdrawn due to psychiatric side effects.

Read the original research

Cannabinoids.

Current drug targets. CNS and neurological disorders, 4(5), 507-30

View on PubMed ↗

Citation

Grotenhermen, Franjo. (2005). Cannabinoids.. Current drug targets. CNS and neurological disorders, 4(5), 507-30.