RT Journal Article SR Electronic T1 Electrophysiological properties of medium spiny neuron subtypes in the caudate-putamen of prepubertal male and female Drd1a-tdTomato line 6 BAC transgenic mice JF eneuro JO eNeuro FD Society for Neuroscience SP ENEURO.0016-19.2019 DO 10.1523/ENEURO.0016-19.2019 A1 Jaime A. Willett A1 Jinyan Cao A1 David M. Dorris A1 Ashlyn G. Johnson A1 Laura A. Ginnari A1 John Meitzen YR 2019 UL http://www.eneuro.org/content/early/2019/03/07/ENEURO.0016-19.2019.abstract AB The caudate-putamen is a striatal brain region essential for sensorimotor behaviors, habit learning, and other cognitive and premotor functions. The output and predominant neuron of the caudate-putamen is the medium spiny neuron (MSN). MSNs present discrete cellular subtypes that show differences in neurochemistry, dopamine receptor expression, efferent targets, gene expression, functional roles, and most importantly for this study, electrophysiological properties. MSN subtypes include the striatonigral and the striatopallidal groups. Most studies identify the striatopallidal MSN subtype as being more excitable than the striatonigral MSN subtype. However, there is some divergence between studies regarding the exact differences in electrophysiological properties. Furthermore, MSN subtype electrophysiological properties have not been reported disaggregated by biological sex. We addressed these questions using prepubertal male and female Drd1a-tdTomato line 6 BAC transgenic mice, an important transgenic line that has not yet received extensive electrophysiological analysis. We made acute caudate-putamen brain slices and assessed a robust battery of 16 relevant electrophysiological properties using whole-cell patch clamp recording, including intrinsic membrane, action potential, and miniature excitatory postsynaptic current (mEPSC) properties. We found that: (1) MSN subtypes exhibited multiple differential electrophysiological properties in both sexes, including rheobase, action potential threshold and width, input resistance in both the linear and rectified ranges, and mEPSC amplitude; (2) select electrophysiological properties showed interactions between MSN subtype and sex. These findings provide a comprehensive evaluation of mouse caudate-putamen MSN subtype electrophysiological properties across females and males, both confirming and extending previous studies.Significance Statement The findings presented here provide the most comprehensive evaluation of the electrophysiological properties of caudate-putamen medium spiny neuron (MSN) subtypes ever performed in a single study, both in terms of electrophysiological metrics and animal sex. These data selectively confirm, diverge from, and extend the findings of previous studies, providing a firm foundation upon which to pursue future studies of caudate-putamen MSNs.