Endothelial atypical cannabinoid receptor: do we have enough evidence?

Area of Science:

• Pharmacology
• Cardiovascular Physiology
• Endocrinology

Background:

• Cannabinoids influence physiological functions, including cardiovascular variables.
• Vascular relaxation by cannabinoids is hypothesized to involve a novel endothelial cannabinoid (eCB) receptor, distinct from CB1 and CB2.
• This receptor is thought to be a G-protein coupled receptor (GPCR) on endothelial cells.

Purpose of the Study:

• To review the evidence for the proposed endothelial cannabinoid (eCB) receptor.
• To highlight discrepancies in the pharmacological profile and signaling pathways of the eCB receptor.
• To emphasize the need for re-evaluation of eCB receptor research in cardiovascular abnormalities.

Main Methods:

• Review of existing literature on cannabinoid receptor research.
• Analysis of studies using pertussis toxin to indicate GPCR-mediated signaling.
• Examination of pharmacological approaches used to attribute vascular relaxation to eCB receptors.

Main Results:

• Evidence for the eCB receptor primarily stems from vascular relaxation studies.
• Recent findings suggest GPCR-independent targets for eCB receptor agonists and antagonists.
• Discrepancies exist regarding the pharmacological profile and signaling of the eCB receptor.

Conclusions:

• The molecular identity and function of the eCB receptor require further rigorous investigation.
• Gi/o protein-independent actions of eCB receptor inhibitors need careful consideration.
• Clarifying eCB receptor signaling is crucial for cardiovascular drug discovery and understanding pathophysiological conditions.