Muscarinic mechanisms in a mouse model of myopia

Abstract

To determine if the level of mRNA for m1-m5 is affected by procedures used for experimental myopia. Experimental myopia was induced by placing a -10D contact lens over the right eyes of 200 mice. Groups were normal, contact lens wearing with or without atropine and a saline control. RT-PCR and northern blot was carried out using specific primers for m1-m5 and products sequenced. Real-time PCR was used to quantify message levels. Axial length of myopic eyes was 111% of their controls and 103% of controls after atropine treatment. RT-PCR and Northern blots showed expression levels of all five mAChRs. Real-time PCR showed that message levels for M1, M3 and M4 were up regulated in atropine treated myopic sclera, but M2 and M5 showed little change. This study confirms that M1-M5 are present in mouse sclera. Atropine may act on one or more mAChRs to differentially regulate expression levels of specific receptors.