In rat neostriatal neurons, D1 dopamine receptors regulate the activity of cyclic AMP-dependent protein kinase (PKA) and phosphatase 1 (PP1). The influence these signaling elements on high voltage-activated (HVA) calcium currents was studied using whole-cell voltage-clamp techniques. application agonists or AMP analogs reversibly reduced N- P-type Ca2+ currents. Inhibition PKA antagonized this modulation, as did inhibition PP1, suggesting that effect mediated by a enhancement PP1 directed...

Most in vitro studies of D1 dopaminergic modulation excitability neostriatal medium spiny neurons have revealed inhibitory effects. Yet made more intact preparations shown that receptors can enhance or inhibit the responses to excitatory stimuli. One explanation for these differences is effects on are dependent changes membrane potential occurring response cortical inputs seen only preparations. To test this hypothesis, we obtained voltage recordings from slices and examined impact receptor...

In spite of the recognition that striatal D 2 receptors are critical determinants in a variety psychomotor disorders, cellular mechanisms by which these shape neuronal activity have remained mystery. The studies presented here reveal receptor stimulation enkephalin-expressing medium spiny neurons suppresses transmembrane Ca 2+ currents through L-type channels, resulting diminished excitability. This modulation is mediated G β γ activation phospholipase C, mobilization intracellular stores,...

Ca2+ currents in acutely isolated, adult rat neostriatal neurons were studied with whole-cell voltage-clamp techniques. In the vast majority of (approximately 90%, n > 250), exclusively high-voltage-activated (HVA) type. HVA activated near -40 mV and reached their maximum amplitude 0 mV. Quasi-steady-state inactivation curves many well fitted only a sum Boltzmann functions, suggesting that heterogeneous. Although block current by Cd2+ was single isotherm having an IC50 1 microM, experiments...

Correlated activity in cortico-basal ganglia circuits plays a key role the encoding of movement, associative learning and procedural memory. How correlated is assembled by striatal microcircuits not understood. Calcium imaging neuronal populations, with single-cell resolution, reveals sporadic asynchronous under control conditions. However, N-methyl-d-aspartate (NMDA) application induces bistability neurons. Widespread neurons within field observation present burst firing. Sets exhibit...

Dopamine is a critical modulator of striatal function; its absence produces Parkinson's disease. Most cellular actions dopamine are still unknown. This work describes the presynaptic dopaminergic receptor agonists on GABAergic transmission between neostriatal projection neurons. Axon collaterals interconnect neurons, main axons which project to other basal ganglia nuclei. if not all these projecting pass through globus pallidus. Thus, we lesioned intrinsic neurons pallidus and stimulated...

In a rat corticostriatal slice, brief, suprathreshold, repetitive cortical stimulation evoked long-lasting plateau potentials in neostriatal neurons. Plateau were often followed by spontaneous voltage transitions between two preferred membrane potentials. While the induction of was disrupted non-NMDA and NMDA glutamate receptor antagonists, maintenance only blocked L-type Ca2+ channel antagonists. The frequency duration depolarized events, resembling up-states described vivo, increased...

It is demonstrated that acetylcholine released from cholinergic interneurons modulates the excitability of neostriatal projection neurons. Physostigmine and neostigmine increase input resistance (RN) enhance evoked discharge spiny neurons in a manner similar to muscarine. Muscarinic RN occurs whole subthreshold voltage range (-100 -45 mV), remains presence TTX Cd2+, can be blocked by relatively selective M1,4 muscarinic receptor antagonist pirenzepine but not M2 or M3 antagonists. Cs+...

Besides a reduction of L-type Ca2+-currents (Ca(V)1), muscarine and the peptidic M1-selective agonist, MT-1, reduced currents through Ca(V)2.1 (P/Q) Ca(V)2.2 (N) Ca2+ channel types. This modulation was strongly blocked by peptide MT-7, specific muscarinic M1-type receptor antagonist but not significantly MT-3, M4-type antagonist. Accordingly, afterhyperpolarizing potential (AHP) decreased GABAergic inhibitory postsynaptic (IPSCs) produced axon collaterals that interconnect spiny neurons....

Circuit properties, such as the selection of motor synergies, have been posited relevant tasks for recurrent inhibitory synapses between spiny projection neurons neostriatum, a nucleus basal ganglia participating in procedural learning and voluntary control. Here we show how dopaminergic system regulates short-term plasticity (STP) these synapses. STP is thought to endow neuronal circuits with computational powers gain control, filtering, emergence transitory net states. But little known...

Neuronal synchronization in basal ganglia circuits plays a key role the encoding of movement, procedural memory storage and habit formation. Striatal dopamine (DA) depletion during Parkinsonism causes abnormal corticobasal loops resulting motor dysfunction. However, dynamics striatal microcircuit underlying is poorly understood. Here we used targeted whole-cell recordings, calcium imaging allowing recording from dozens cells simultaneously analytical approaches, to describe striking...

Abstract Direct pathway striatal projection neurons (dSPNs) are characterized by the expression of dopamine (DA) class 1 receptors (D R), as well cholinergic muscarinic M and 4 (M R, R). D R enhances neuronal firing through phosphorylation voltage‐gate calcium channels (Ca V Ca 2+ channels) activating Gs proteins protein kinase A (PKA). Concurrently, PKA suppresses phosphatase PP‐1 DARPP‐32, thus extending this facilitatory modulation. also influences in SPNs Gq C. However, signaling...

1. Intracellular recordings from neostriatal neurons in an vitro slice preparation of the rat brain were used to analyze pharmacological sensitivity action potential (AP) repolarization and afterhyperpolarization (AHP) that follows a single potential. The interspike voltage trajectory AHP could be divided into two main parts: fast component lasting few milliseconds better observed during train spikes, slow approximately 250 ms comprises portion AHP. In some cells, (up 1 s) low amplitude was...

Selection and inhibition of motor behaviors are related to the coordinated activity compositional capabilities striatal cell assemblies. Striatal network represents a main step in basal ganglia processing. The dopaminergic system differentially regulates distinct populations medium spiny neurons (MSNs) through activation D 1 - or 2 -type receptors. Although postsynaptic presynaptic actions these receptors clearly different MSNs during cell-focused studies, their has shown inconsistent...

Inhibitory connections among striatal projection neurons (SPNs) called “feedback inhibition,” have been proposed to endow the microcircuit with computational capabilities, such as motor sequence selection, filtering, and emergence of alternating network states. These properties are disrupted in models Parkinsonism. However, impact feedback inhibition has remained under debate. Here, we test this at level. We used optical electrophysiological recordings mice rats demonstrate action...

The effects of activating dopaminergic D1 and D2 class receptors the subthalamic projections that innervate pars reticulata subtantia nigra (SNr) were explored in slices rat brain using whole cell patch-clamp technique. Excitatory postsynaptic currents (EPSCs) could be blocked by 6-cyano-7-nitroquinoxalene-2,3-dione D-(-)-2-amino-5-phosphonopentanoic acid evoked onto GABAergic projection neurons local field stimulation inside nucleus presence bicuculline. Bath application...