Expression of m1 and m4 muscarinic receptor mRNA in the striatum following a selective lesion of striatonigral neurons

Abstract

Cholinergic stimulation has opposing effects on striatopallidal and striatonigral neurons. Most striatal projection neurons express m1 muscarinic receptor mRNA with m4 mRNA found in 40-50%. Expression of m4 mRNA is found in most preprotachykinin neurons but only a subset of preproenkephalin neurons, suggesting preferential localization of m4 receptors to striatonigral neurons. A volkensin lesion of striatonigral neurons reduced striatal m4 mRNA by 63% and m1 mRNA by only 18%, suggesting that preferential expression of m4 receptors by striatonigral neurons may contribute to their differential response.