Figure 4. Muscarinic receptor sub-types transcript levels in mouse sclera. The bar graph compares the relative gene expression of mouse scleral muscarinic receptor subtypes to the corresponding mouse brain mRNA level (range) after normalization with 18S rRNA internal standard. The mRNA level of M₁, M₃, and M₄ in mouse sclera was less than in the mouse brain. However, the mRNA level of M₂ and M₅ was abundant in the mouse sclera.