Electrophysiological and morphological characteristics and synaptic connectivity of tyrosine hydroxylase-expressing neurons in adult mouse striatum.
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 approximately 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 GABA(A) 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.
Ibáñez-Sandoval
Osvaldo
O
Center For Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, New Jersey 07102, USA.
Tecuapetla
Fatuel
F
Unal
Bengi
B
Shah
Fulva
F
Koós
Tibor
T
Tepper
James M
JM
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D001640:Bicuculline / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002317:Cardiovascular Agents / Q000494:pharmacology; D002452:Cell Count / Q000379:methods; D003078:Colchicine / Q000494:pharmacology; D003342:Corpus Striatum / Q000166:cytology* / Q000187:drug effects; D004558:Electric Stimulation / Q000379:methods; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005439:Flufenamic Acid / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000235:genetics; D066298:In Vitro Techniques; D008239:Lysine / Q000031:analogs & derivatives / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000145:classification / Q000166:cytology* / Q000502:physiology*; D009553:Nimodipine / Q000494:pharmacology; D018408:Patch-Clamp Techniques / Q000379:methods; D011743:Pyrimidines / Q000494:pharmacology; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects; D013997:Time Factors; D050257:Tubulin Modulators / Q000494:pharmacology; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics / Q000378:metabolism*; D050493:Vesicular Monoamine Transport Proteins / Q000235:genetics / Q000378:metabolism
D000893:Anti-Inflammatory Agents; D002121:Calcium Channel Blockers; D002317:Cardiovascular Agents; D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D011743:Pyrimidines; D050257:Tubulin Modulators; D050493:Vesicular Monoamine Transport Proteins; C485184:enhanced green fluorescent protein; C082246:ICI D2788; D049452:Green Fluorescent Proteins; D009553:Nimodipine; D005439:Flufenamic Acid; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D014446:Tyrosine 3-Monooxygenase; C013411:biocytin; D008239:Lysine; D003078:Colchicine; D001640:Bicuculline