Dopamine-dependent synaptic plasticity in the striatal cholinergic interneurons

Area of Science:

• Neuroscience
• Cellular and Molecular Biology
• Synaptic Plasticity

Background:

• The striatum, a key basal ganglia component, is vital for habit learning and skill acquisition.
• Dopamine (DA) and acetylcholine (ACh) are crucial for implicit memory, but cellular mechanisms remain elusive.
• Cholinergic interneurons in the striatum play a significant role in modulating synaptic transmission.

Purpose of the Study:

• To investigate long-term synaptic changes in identified striatal cholinergic interneurons.
• To determine the effects of tetanic stimulation on cortico- and thalamostriatal fibers.
• To elucidate the cellular mechanisms underlying synaptic plasticity in the striatum.

Main Methods:

• Patch-clamp recordings were performed on corticostriatal slices from mice.
• Tetanic stimulation was applied to cortico- and thalamostriatal fibers.
• Postsynaptic potentials (EPSPs and IPSPs) in cholinergic interneurons were analyzed.

Main Results:

• Tetanic stimulation induced simultaneous long-term potentiation (LTP) of glutamatergic EPSPs and disynaptic GABAergic IPSPs.
• LTP induction required intracellular Ca(2+) and dopamine D(5) receptor activation, not D(2) receptors.
• Enhanced disynaptic IPSPs resulted from an increased occurrence rate, not amplitude, in cholinergic interneurons.

Conclusions:

• Striatal cholinergic interneurons exhibit dual synaptic plasticity mechanisms (LTP of EPSPs and enhanced IPSPs).
• This plasticity is modulated by Ca(2+) influx and dopamine D(5) receptor signaling.
• These findings offer insights into the cellular basis of implicit memory and skill learning in the striatum.