Related Experiment Video
Updated: Feb 20, 2026
3D Visualization of Retinal Vascular Pericytes in Mice by Immunostaining
Published on: November 1, 2024
Cannabinoids Regulate the Diameter of Pericyte-Containing Retinal Capillaries in Rats
Yuan Zong1,2, Xujiao Zhou3,2, Jingyi Cheng1,2
1Department of Ophthalmology and Vision Science, Eye and ENT Hospital, Fudan University, Shanghai, China.
Background/Aims:
Cannabinoids are vasoactive substances that act as key regulators of arterial tone in the blood vessels supplying peripheral tissues and the central nervous system. We therefore investigated the effect of cannabinoids on retinal capillaries and pericytes.
Methods:
The effects of cannabinoids on capillary diameters were determined using an ex vivo whole-mount rat retinal model. Western blotting, quantitative PCR, and immunohistochemistry were performed to explore the underlying mechanism.
Results:
Endogenous cannabinoid 2-arachidonoylglycerol and anandamide and exogenous cannabinoid (R-(+)-WIN55212-2) dilated the noradrenaline-precontracted capillaries in a concentration-dependent manner (1 µM to 0.1 mM). The extent of vasorelaxation was positively correlated with changes in pericyte width. The effects of R-(+)-WIN55212-2 on vasorelaxation and pericyte width were inhibited by a cannabinoid receptor type-1 (CB1) antagonist, AM251 or rimonabant (SR141716A), the nitric oxide synthase inhibitor l-NAME, and the guanylate cyclase inhibitor ODQ. They were also abolished by the removal of the endothelium, but not by the cannabinoid receptor-2 antagonist SR144528, the endothelial cannabinoid receptor antagonist O-1918, or the cyclooxygenase inhibitor indomethacin.
Conclusion:
The exogenous cannabinoid R-(+)-WIN55212-2 promotes the vasorelaxation of pericyte-containing rat retinal capillaries. This effect of R-(+)-WIN55212-2 is dependent on CB1 and the nitric oxide-cyclic guanosine monophosphate pathway, and requires an intact endothelium.
