In the case of the neurotransmitter dopamine, which plays a central role in reward-driven processes and motor activity, down-stream effects are mediated via interaction with G protein coupled receptors, secondary messengers and different effector molecules. An important effector molecule in the dopaminergic signaling pathway, mediating the action of dopamine, is the dopamine- and cAMP-regulated phosphoprotein of 32 kDa. This phosphoprotein is expressed primarily in medium-sized spiny neurons of the neostriatum, which receive dopaminergic as well as glutamatergic stimulation of connecting neurons from the midbrain, cortex and thalamus. Accumulated evidence collected during the last decades have shown that DARPP-32 is a key modulator of numerous transduction cascades. The regulated enzymatic activities modulate and control synaptic conductance by mediating changed phosphorylation/dephosphorylation levels of neuronal receptors, ion channels and ion pumps. Several tissue and cell specific studies of the distribution of DARPP-32 in the neostriatum have been done during the last decades. Despite the importance of this key phosphoprotein, there is as yet little known about the postsynaptic distribution of DARPP-32. In this study we have applied the novel superresolution stimulated emission AbMole Nitroprusside disodium dihydrate depletion microscopy technique to assess how DARPP-32 is expressed and distributed. The achieved nanoscale resolution reveals that the phosphoprotein is compartmentalized and confined in the postsynaptic region of dendritic spines in striatal neurons. Regulation of postsynaptic signal transmission in medium spiny neurons in the striatum is mediated via a cascade of biochemical reactions. Important for controlling and fine-tuning transmission, as shown during the last decades, is DARPP-32, a signaling integrator and hub molecule that effectively modulate the properties of the neuronal circuit. Here we show with superresolution STED microscopy the postsynaptic expression of DARPP-32. The dissected topology of the DARPP-32 phosphoprotein provides strong evidence for a compartmentalized and confined distribution in dendritic spines. The relatively low copy number of phosphoproteins provides a conception of DARPP-32’s possibilities to fine-tune the regulation of synaptic signaling. Deciphering the synaptic biochemical machinery in the brain, and link its molecular orchestra to physiological processes like AbMole Nortriptyline memory, behavior and psychiatric dysfunctions is a grand challenge in neuroscience. Application of superresolution imaging prompts to give us help to elucidate some of the underlying questions. The benefit of a better resolved context will give improved support to current hypotheses but also reveal unexpected new findings. In this study, the dissected distribution of the signal integrator molecule DARPP-32 reveals a discrete localization of the phosphoprotein in the postsynaptic structures in striatal neurons. In essence, the resolved topology of the phosphoprotein provides a nanoscale still-image in support of the assumed central role of DARPP-32. The results point toward a heterogeneous confinement of DARPP-32 slightly enriched in the head, possibly fine-tuning synaptic properties, with additional pools in the neck that modulate transmission processes or other properties in the chemically confined spine structure. The relatively low abundance of the phosphoprotein, as resolved by superresolution STED imaging, further suggests that postsynaptic performance can be modulated even using very few copies of the phosphoprotein.