Journal: The Journal of Neuroscience

Article Title: NR2A^−/−Mice Lack Long-Term Potentiation But Retain NMDA Receptor and L-Type Ca²⁺Channel-Dependent Long-Term Depression in the Juvenile Superior Colliculus

doi: 10.1523/jneurosci.3153-07.2007

Figure Lengend Snippet: Figure 3. NMDAR and L-type Ca 2 channel-dependent LTP is present in WT but not inNR2A/ SC neurons.A, E, In WT SC, only 20 Hz at 30–50% ST induced LTP (126.5 6.9, n 10 and 3, p 0.004), 20 Hz at 80–90% ST produced a small but significantdepression(92.22.1,n6and2,p0.01),10Hzat30–50%STproducednochangefrombaseline(95.43.1, n5and2,p0.2),and50Hzat30–50%producedasignificantLTD(82.35.6,n9and3,p0.02).Sampletracesare averagesof30evokedEPSPsobtainedduringthe10minofbaseline(1)and30–40minafterinduction(2)with20Hzat30–50% ST (calibration: 10 mV, 50 ms). For all parts of Figure 3, stimulus intensity is given as percentage of ST identified as percentage alone,andallstimuliare20sinduration.EPSPslopeisgivenaspercentagechangefrombaseline(averageevokedEPSCduring10 min baseline over average EPSP slope 30–40 min after induction). B, E, In NR2A/ SC, four of five stimulation protocols producednosignificantchangefrombaseline(20Hzat30–50%ST,102.75.9,n9and3,p0.68;20Hzat80–90%ST, 90.16.7,n6and2,p0.22;10Hzat30–50%ST,94.74.5,n5and2,p0.35;and20Hz30–50%STinthepresence of Nim, 97 4.6, n 8 and 2, p 0.51). The exception was 50 Hz at 30–50% ST, which produced an LTD (81.1 6.1, n 8 and3,p0.02)similartothatseenwith50HzstimulationinWT.Sampletracesareaveragesof30evokedEPSPsobtainedduring the10minofbaseline(1)and30–40minafterinduction(2)with20Hzat30–50%ST(calibrationbar:10mV,50ms).C,E,InWT neurons,LTPinductionwith20Hzat30–50%waspreventedbyAP-5alone(94.94.8,n7and2,p0.36)orAP-5plusNim (98.9 4.8, n 8 and 2, p 0.81) and reversed to LTD by Nim alone (78.7 5, n 8 and 3, p 0.01) or Nim plus Ro 25 (74.45.6,n9and3,p0.01).D,Top,InWTneurons,LTPinductionwith20Hzat30–50%STcouldbereversedtoLTDby Nim use before induction (85.7 4.1, n 6 and 2, p 0.02). Bottom, All plasticity was prevented by Nim application after induction (92.1 4.6, n 6 and 2, p 0.18). E, Summary of mean EPSP slope changes from baseline at 30–40 min after induction under the different conditions in WT and NR2A/ SC neurons. Each open diamond represents an individual experi- ment, and filled diamonds are the means of all the experiments in that group. All stimuli are at 30–50% ST except when noted. Allstimulationfrequenciesare20Hzunlessotherwisestated,andallstimulationdurationsare20s.Pre-NimandPost-Nim,Before and after induction application of Nimodipine. Paired-sample, two-tailed Student’s t test.

Article Snippet: AP-5 (NMDAR antagonist, 100 M; Sigma), nimodipine (Nim) (L-type Ca 2 channel antagonist, 20 M; Tocris Bioscience), and Ro 25-6981 [R-( R, S)- -(4-hydroxyphenyl)- - methyl-4-(phenylmethyl)-1-piperidine propranol] (Ro 25) (NR2B NMDAR antagonist, 5 M; Sigma) were used as noted.

Techniques: Produced, Two Tailed Test