Cannabinoid receptor CB 1 mRNA is highly expressed in the rat ciliary body: implications for the antiglaucoma properties of marihuana

Abstract

We used RT-PCR to measure relative differences in cannabinoid receptor (CB) mRNAs in the rat eye, comparing CB 1 or CB 2 transcripts to that of the normalizing reference gene β 2 microglobulin (β 2m). Significantly higher levels of CB 1 mRNA levels were found in the ciliary body (0.84±0.05% of β 2m) than in the iris, (0.34±0.04% of β 2m), retina (0.07±0.005% of β 2m) and choroid (0.06±0.005% of β 2m). CB 2 mRNA was undetectable. This expression pattern supports a specific role for the CB 1 receptor in controlling intraocular pressure, helping to explain the antiglaucoma property of cannabinoids.