OPPOSING EFFECTS OF STRIATONIGRAL FEEDBACK PATHWAYS ON MIDBRAIN DOPAMINE CELL-ACTIVITY
OPPOSING EFFECTS OF STRIATONIGRAL FEEDBACK PATHWAYS ON MIDBRAIN DOPAMINE CELL-ACTIVITY
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DOI：
10.1016/0006-8993(85)91581-1
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发表时间：
1985-01-01
期刊：
影响因子：
2.9
通讯作者：
BUNNEY, BS
中科院分区：
文献类型：
--
作者：
GRACE, AA;BUNNEY, BS
The existence of a striatonigral GABAergic pathway is well established anatomically and biochemically. During intracellular recording from identified DA [dopamine] neurons in vivo, stimulation of the striatum (100 .mu.A, 50 .mu.s pulses) elicits an inhibitory postsynaptic potential (IPSP) and a rebound depolarization. The IPSP is a short latency (1.8-2.2 ms) conductance increase to chloride, since: the reversal potential is near the chloride reversal potential reported for other cells (-68 mV); intracellular chloride injection progressively reverses the IPSP into a depolarization with a similar time course; and the response of DA cells to systemic injection of the cloride channel blocker, picrotoxin, also exhibits a similar reversal potential. In contrast, during extracellular recording, stimulation of the striatum at low levels of intensity (e.g., 20 .mu.A at 10 Hz) increases the firing rate of DA cells. Stimulation of the striatum will, in addition, elicit IPSP in a subclass of substantia nigra zona reticulata neurons at the same latency as the IPSP triggered in DA cells. The IPSP also reverse with intracellular chloride injection. However, their amplitude is larger and their duration longer than observed in DA cells; there is no depolarizing rebound. The late component of the IPSP in the zona reticulata neurons corresponds temporally to the rebound depolarization seen in DA cells in response to striatal stimulation. In addition, when recorded extracellularly, striatal stimulation will inhibit the firing of this class of zona reticulata interneurons at the same stimulation parameters that will excite DA cells. Striatal cells evidently may send branched fast-conducting GABAergic projections to zona reticulata cells and DA cells. Low levels of striatal stimulation can excite DA cells by preferentially inhibiting interneurons in the zona reticulata which are more sensitive to the inhibitory effects of GABA than are DA neurons.
