One of the main difficulties of addiction treatment is the high risk of relapse even after a long abstinence. Therefore, discovering the underlying molecular principles of relapse is essential. The metabotropic glutamate receptor, mGluR5, is considered to play an important role in this aspect. One of the brain structures expressing mGluR5 is the striatum, an area which is largely composed of medium-sized spiny neurons (MSNs). These neurons are divided into two major subpopulations characterized based on their projections and protein properties. In our constellation, we have generated a mouse line designed to have a selective mGluR5 knock-down in one of these populations – the dopamine D1 receptor (D1R) expressing neurons. It has however been unclear if the expression of transgene is indeed limited to only D1R-expressed neurons. By immunofluorescence, we here show that in the striatum the construct is expressed only in MSNs and is restricted to the D1R-expressing cell population. Thus the transgenic mouse line is a good tool for the study of mGluR5 selectively in D1R expressing neurons.