PMC

The activation of a Ca²⁺ sensitive PKC isoform such as PKCα by paired pulse-facilitated additional Ca²⁺ influx interacts with downstream effectors of DOR to eliminate FSI-MSN DOR-LTD. We hypothesize that this PKC isoform is localized close to Ca²⁺ channels by interacting with the scaffolding protein, PICK1. Because EtOH produces LTD at the FSI-MSN synapse through the activation of DOR, PKC activity also eliminates EtOH-induced LTD.

(A) Left: Delivering paired light pulse stimulation eliminated EtOH-induced LTD (blue) compared to delivering single pulse light stimulation (black). Right: Scatterplot depicting the change in oIPSC strength from minutes 25–30 for each cell in single (black) and paired (blue) light pulse delivery experiments. (B) Left: BIM-1 (2 µM) in the aCSF eliminated EtOH-induced LTD while delivering a paired light pulse stimulation (blue). Control paired pulse data from (A) is represented as mean ± SEM (black). Right: Scatterplot showing the change in oIPSC amplitude from baseline (black) following EtOH wash (blue) in each neuron recorded. All scale bars: 200 pA, 200 ms. * p < 0.05. All representative traces are dark from the first 5 minutes and light from the last 5 minutes of the experiment. Scatterplots: open circles are individual cells, filled circles are mean ± SEM.

(A) Right: Paired light pulse stimulation (blue shaded region) following a 5 min baseline of single light pulse stimulation did not produce lasting synaptic changes. Right: Scatterplot depicting no significant effect of pulse number on oIPSC amplitude (single pulse, black; paired pulse, blue). (B) Left: Paired electrical pulse stimulation (blue shaded region) following a 5 min baseline of single electrical pulse stimulation had no effect on eIPSC amplitude. Right: Scatterplot depicting no effect of electrical stimulation pulse number on eIPSC amplitude (single pulse, black; paired pulse, blue). All scale bars: 200 pA, 200 ms. n.s.: not significant. All representative traces are dark from the first 5 minutes and light from the last 5 minutes of the experiment. Scatterplots: open circles are individual cells, filled circles are mean ± SEM.

(A) Left: Incubating slices in BIM-1 (2 µM) eliminated the paired light pulse-induced protection against DOR-LTD (blue). Control paired pulse data from () are represented as mean ± SEM in black. Right: Scatterplot depicting the change in oIPSC amplitude from baseline (black) following DPDPE wash in each neuron recorded (blue). (B) Left: Delivering paired light pulses in artificial cerebrospinal fluid (aCSF) containing 0 mM Ca²⁺ and 2 mM Sr²⁺ eliminated the protection against DOR-LTD. Right: Scatterplot depicting the change in oIPSC amplitude from baseline (black) following DPDPE wash (blue) in each neuron recorded. (C) Left: In the presence of the PKC inhibitor Go 6976 (3 µM) the paired light pulse protection against DOR-LTD was eliminated. Control paired pulse data from () are represented as mean ± SEM in black. Right: Scatterplot showing the change in oIPSC amplitude from baseline (black) following DPDPE wash (blue) in each neuron recorded. (D) Left: Incubating slices in the blocking peptide TAT-PKC-CT (1 µM; blue) eliminated paired pulse protection against DOR-LTD. This protection was intact following incubation in a truncated control peptide TAT-PKCdeltaCT (1 µM; black). Right: Scatterplot depicting the change in oIPSC strength from minutes 25–30 for each cell in both experimental conditions (control peptide, black; blocking peptide, blue). (E) Left: Incubation in TAT-PKC-CT did not lead to synaptic depression in the absence of DPDPE. Right: Scatterplot showing no change in oIPSC amplitude from baseline (black) and minutes 25–30 (blue) in each neuron recorded. Scatterplots: all open circles are individual cells and filled circles are mean ± SEM. All dark representative traces are from the first 5 minutes and light traces are from the last 5 minutes of the experiment. All scale bars: 200 pA, 200 ms. * p < 0.05, *** p < 0.0005, n.s.: not significant.

(A) To optogenetically target fast-spiking interneurons (FSI) in the dorsolateral striatum (DLS), an adeno-associated viral (AAV) vector containing a double loxP flanked (dFlx)-channelrhodopsin (ChR2) construct was injected into the DLS of parvalbumin (PV)-cre mice. Optogenetically-evoked inhibitory postsynaptic currents (oIPSC) arising from FSIs were recorded from medium spiny neurons (MSNs). (B) Left: Delivering paired light pulses (50 ms inter-pulse interval) blocked DOR-LTD induced by DPDPE (500 nM) (blue) compared to single light pulse interrogation of the synapse (black). Scale bars: 200 pA, 200 ms. Right: Scatterplot depicting the change in oIPSC strength from minutes 25–30 for each cell in single (black) and paired (blue) light pulse delivery experiments. (C) Left: Delivering paired electrical pulses (blue) abolished DOR-LTD compared to single electrical pulse stimulation (black). Scale bars: 200 pA, 200 ms. Right: Scatterplot depicting the change in electrically-evoked IPSC (eIPSC) strength from minutes 25–30 for each cell in single (black) and paired (blue) electrical pulse delivery experiments. (D) Left top: Schematic of the recording configuration in Aplysia californica. Left bottom: Single electrical pulse interrogation of the Aplysia siphon sensory neuron-to-motor neuron synapse resulted in synaptic depression (black) that attenuated with 2 bursts of action potentials (light blue) and eliminated with bursts of 4 action potentials (dark blue) (50 ms interpulse interval). Right: Representative postsynaptic potentials (PSPs) from each condition. Scale bars: 400 pA, 200 ms. * p < 0.05. B, C: representative traces are dark from the first 5 minutes and light from the last 5 minutes of the experiments. B, C scatterplots: open circles are individual cells, filled circles are mean ± SEM. D: data are represented as mean ± SEM.