has soma location has soma location expresses expresses striatum neuron medium spiny neuron D1-NUDAP medium spiny neuron A DRD1-expressing medium spiny neuron that is part of dense, RXFP1-positive cell islands throughout the nucleus accumbens, putamen, and near the adjacent septal nuclei. Regarding the abbreviation D1-NUDAP, NUDAP stands for "neurochemically unique domains in the accumbens and putamen". In Rhesus macaques, the RXFP1-positive interface island D1-medium spiny neuron (D1-NUDAP) has been noted to have upregulation of OPRM1 compared to DRD1-expressing medium spiny neurons located outside of the D1-exclusive island and in Islands of Calleja. Kappa-opioid receptor gene (OPRK1) has been noted to be absent from D1-NUDAP cells. Many striosome-specific markers have been noted to be upregulated in D1-NUDAP cells, including KCNIP1, KCNT1, KHDRBS3, and BACH2. PDYN, an acknowledged D1-striosome marker gene, has also been noted to be expressed in D1-NUDAPs. D1-NUDAPs also express some genes found to be selectively expressed in the matrix, including STXBP6, GDA, and SEMA3E. Gene enrichment analysis has revealed that D1-NUDAP neurons express genes that have been implicated in drug addiction and many other functions. RXFP1-positive interface island D1-medium spiny neuron D(1A) dopamine receptor relaxin receptor 1 ventral striatum