I(h) channels contribute to the different functional properties of identified dopaminergic subpopulations in the midbrain.

摘要: Dopaminergic (DA) midbrain neurons in the substantia nigra (SN) and ventral tegmental area (VTA) are involved various brain functions such as voluntary movement reward targets disorders Parkinson's disease schizophrenia. To study functional properties of identified DA mouse slices, we combined patch-clamp recordings with either neurobiotin cell-filling triple labeling confocal immunohistochemistry, or single-cell RT-PCR. We discriminated four subpopulations based on anatomical neurochemical differences: two calbindin D28-k (CB)-expressing populations (SN/CB+) (VTA/CB+), respectively, negative (SN/CB-, VTA/CB-). VTA/CB+ displayed significantly faster pacemaker frequencies smaller afterhyperpolarizations compared other neurons. In contrast, all possessed significant differences I(h) channel densities channel-mediated like sag amplitudes rebound delays following order: SN/CB- --> VTA/CB- SN/CB+ VTA/CB+. Single-cell RT-multiplex PCR experiments demonstrated that differential but not calretinin expression is associated densities. Only neurons, however, channels were actively frequency control. conclusion, diversity within system restricted to distinct axonal projections synaptic connectivity, also involves postsynaptic conductances between neurochemically topographically