RT Journal Article
SR Electronic
T1 Electrophysiological and Morphological Characteristics and Synaptic Connectivity of Tyrosine Hydroxylase-Expressing Neurons in Adult Mouse Striatum
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 6999
OP 7016
DO 10.1523/JNEUROSCI.5996-09.2010
VO 30
IS 20
A1 Osvaldo Ibáñez-Sandoval
A1 Fatuel Tecuapetla
A1 Bengi Unal
A1 Fulva Shah
A1 Tibor Koós
A1 James M. Tepper
YR 2010
UL http://www.jneurosci.org/content/30/20/6999.abstract
AB Whole-cell recordings were obtained from tyrosine hydroxylase-expressing (TH+) neurons in striatal slices from bacterial artificial chromosome transgenic mice that synthesize enhanced green fluorescent protein (EGFP) selectively in neurons expressing TH transcriptional regulatory sequences. Stereological cell counting indicated that there were ∼2700 EGFP–TH+ neurons/striatum. Whole-cell recordings in striatal slices demonstrated that EGFP–TH+ neurons comprise four electrophysiologically distinct neuron types whose electrophysiological properties have not been reported previously in striatum. EGFP–TH+ neurons were identified in retrograde tracing studies as interneurons. Recordings from synaptically connected pairs of EGFP–TH+ interneurons and spiny neurons showed that the interneurons elicited GABAergic IPSPs/IPSCs in spiny neurons powerful enough to significantly delay evoked spiking. EGFP–TH+ interneurons responded to local or cortical stimulation with glutamatergic EPSPs. Local stimulation also elicited GABAA IPSPs, at least some of which arose from identified spiny neurons. Single-cell reverse transcription-PCR showed expression of VMAT1 in EGFP–TH+ interneurons, consistent with previous suggestions that these interneurons may be dopaminergic as well as GABAergic. All four classes of interneurons were medium sized with modestly branching, varicose dendrites, and dense, highly varicose axon collateral fields. These data show for the first time that there exists in the normal rodent striatum a substantial population of TH+/GABAergic interneurons comprising four electrophysiologically distinct subtypes whose electrophysiological properties differ significantly from those of previously described striatal GABAergic interneurons. These interneurons are likely to play an important role in striatal function through fast GABAergic synaptic transmission in addition to, and independent of, their potential role in compensation for dopamine loss in experimental or idiopathic Parkinson's disease.