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Input Receptors |
Intrinsic Currents |
Output Transmitters |
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Distal equivalent dendrite
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Neocortical Superficial Pyramidal Neuron terminals (T) and Thalamic Relay Neuron terminals (T)
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Glutamate
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| From cerebral cortex (McGeer PL et al, 1977 [mammal]1 ). |
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Substantia Nigra Dopaminergic Cell terminals (T)
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D1
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| Input from dopaminergic neurons in the substantia nigra; causes small depolarization? sometimes a decrease in firing rate; modulates anomalous rectification of dendritic membrane (I IR)? |
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I h
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| Large EPSPs activate I IR, increasing the membrane resistance, shortening the dendrites electrotonically, making the cell more sensitive to subsequent inputs (see |
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Middle equivalent dendrite
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Neocortical Superficial Pyramidal Neuron terminals (T) and Thalamic Relay Neuron terminals (T)
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Glutamate
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| From cerebral cortex (McGeer PL et al, 1977 [mammal]1 ). |
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Substantia Nigra Dopaminergic Cell terminals (T)
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D1
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| Input from dopaminergic neurons in the substantia nigra; causes small depolarization? sometimes a decrease in firing rate; modulates anomalous rectification of dendritic membrane (I IR)? |
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I h
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| Large EPSPs activate I IR, increasing the membrane resistance, shortening the dendrites electrotonically, making the cell more sensitive to subsequent inputs (see |
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Proximal equivalent dendrite
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Neocortical Superficial Pyramidal Neuron terminals (T) and Thalamic Relay Neuron terminals (T)
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Glutamate
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| From cerebral cortex (McGeer PL et al, 1977 [mammal]1 ). |
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Substantia Nigra Dopaminergic Cell terminals (T)
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D1
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| Input from dopaminergic neurons in the substantia nigra; causes small depolarization? sometimes a decrease in firing rate; modulates anomalous rectification of dendritic membrane (I IR)? |
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I h
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| Large EPSPs activate I IR, increasing the membrane resistance, shortening the dendrites electrotonically, making the cell more sensitive to subsequent inputs (see |
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Soma
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D1
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| Activation of both D1- and D2-class receptors has been shown to modulate potassium and sodium currents in acutely isolated neostriatal neurons (Surmeier DJ and Kitai ST, 19932 ). Recordings in slices showed that D1 receptor activation can either inhibit or enhance evoked activity, depending on the level of membrane depolarization, by modulating an L-type Ca2+ conductance (Hernández-López S et al, 19973 ). |
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D2
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| Activation of both D1- and D2-class receptors has been shown to modulate potassium and sodium currents in acutely isolated neostriatal neurons (Surmeier DJ and Kitai ST, 19932 ). |
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Gaba
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| GABAergic responses evoked by electrical stimulations have been studied in slices (Kita T et al, 19854 ). |
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Muscarinic
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| Recording from dissociated neurons using intracellular and whole-cell voltage-clamp recordings showed that carbachol can act at M1-like muscarinic receptors to reduce the membrane K+ conductances and excite the neostriatal neurons (Hsu KS et al, 1996 [rat]5 ). |
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I K
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I Na,t
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| Kinetic properties were studied using the whole-cell patch-clamp technique (Ogata N and Tatebayashi H, 1990 [guinea pig]6 ). |
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I L high threshold
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| Whole-cell voltage-clamp recordings showed that HVA currents were present in at least 95% of neostriatal neurons, but that the majority of them appeared to belong neither to the "L-type" nor the "N-type" classification (Hoehn K et al, 1993 [rat]8 ). However, recordings in slices showed that D1 receptor activation can either inhibit or enhance evoked activity, depending on the level of membrane depolarization, by modulating an L-type Ca2+ conductance (Hernández-López S et al, 19973 ). |
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I N
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| Whole-cell voltage-clamp recordings showed that HVA currents were present in at least 95% of neostriatal neurons, but that the majority of them appeared to belong neither to the "L-type" nor the "N-type" classification (Hoehn K et al, 1993 [rat]8 ). |
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I T low threshold
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| Whole-cell voltage-clamp recordings showed that a low-threshold transient (T-type) Ca2+ current was observed in 40% of neurons (Hoehn K et al, 1993 [rat]8 ). Another study suggested that adult neostriatal projection neurons do not express significant levels of LVA Ca2+ current (Bargas J et al, 1994 [rat]9 ). |
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I A
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| The contribution of a fast (IAt), and a slowly (IAs)-inactivating A-currents were studied in slices. The results suggest a role for these currents to define the limits on the depolarized state (Nisenbaum ES and Wilson CJ, 199510 ). With whole-cell patch clamp, two types of A-current were found in rat neostriatal neurons, one similar to previous descriptions in mammals and a second activated at considerably more depolarized potentials (Surmeier DJ et al, 198911 ). A slowly inactivating A current has also been studied (Gabel LA and Nisenbaum ES, 199812 ). |
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I h
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| The contribution of an inwardly rectifying current (IKir) were studied in slices. The results suggest that the hyperpolarized state is determined principally by this current (Nisenbaum ES and Wilson CJ, 199510 ). |
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I Potassium
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| A slow, noninactivating current may have a role to define the limits on the depolarized state, and to govern the spike discharge characteristics once the depolarized state has been reached (Nisenbaum ES and Wilson CJ, 199510 ). A non-inactivating, Ca-independent, K+ current may limit the amplitude of membrane depolarizations associated with prolonged excursions into the depolarized state (Nisenbaum ES et al, 1996 [rat]13 ). |
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I Calcium
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| Whole cell recordings from acutely dissociated neurons exhibited a R-type currents that were characterized as HVA by their rapid deactivation kinetics, half-activation and half-inactivation voltages, and sensitivity to depolarized holding potentials. In neocortical pyramidal neurons these currents inactivated at more negative potentials than in medium spiny neurons (Foehring RC et al, 200014 ). |
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I K,Ca
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| Calcium-dependent potassium channels are preferentially activated by calcium entry through N- and Q-type channels (Vilchis C et al, 200015 ). |
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I N
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| Calcium-dependent potassium channels are preferentially activated by calcium entry through N- and Q-type channels (Vilchis C et al, 200015 ). |
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I p,q
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| Calcium-dependent potassium channels are preferentially activated by calcium entry through N- and Q-type channels (Vilchis C et al, 200015 ). |
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I Na,p
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| Nomarski optics and infrared videomicroscopy were used to demonstrate the existence of a TTX-sensitive persistent Na+ conductance (INaP) in identified medium-sized neostriatal neurons (Cepeda C et al, 199516 ). |
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Axon hillock
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Axon fiber
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Axon terminal
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Gaba
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Indirect spiny neurons, globus pallidus external neuron, globus pallidus internal neuron, substantia nigra reticulata neurons
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