Figure 3
Tspyl2 mutation impairs long term potentiation (LTP).
(A), Membrane excitability of hippocampal CA1 neurons was measured by whole-cell patch-clamp recording in 2-month old mice. Series of current steps between −160 pA and +160 pA (−55 mV) in 20 pA increments were applied. No difference was observed between wild-type and mutant in action potential (n = 4 each). Three representative recorded action potentials (40, 100, 160 pA) were shown on the right. (B), Input resistance of hippocampal CA1 neurons was measured by whole-cell patch-clamp recording in 2- month old mice at a current of −60 mV. No significant difference was observed between wild-type and mutant (n = 43 for +/Y, n = 34 for m/Y). (C), Basal synaptic transmission was compared by the field excitatory post-synaptic potential (fEPSP)-stimulation relationship. No significant differences were observed between the two groups throughout the range of stimulation intensities. There was also no difference between the fEPSP to fiber volley ratio between the two groups (10 slices from 3 +/Y mice, 12 slices from 3 m/Y mice). (D), The paired-pulse ratio of the evoked fEPSP was not affected by the mutation (10 slices from 3 +/Y mice, 12 slices from 3 m/Y mice). (E), LTP of 2-month old male and female mice. FEPSP was measured from the dendritic layer of CA1 neurons in the Schaffer collateral pathway. Period 1 was the baseline fEPSP while period 2 was the fEPSP after induction. Arrow indicated the electrical stimulation (1 train, 100 Hz, 1 s). Representative recorded potentials were shown on the top. (F), Quantitative change in the average amplitude of the fEPSP taken from 50 to 60 min after induction. LTP was impaired in the mutant (n = 12 for male, n = 9 for female). Error bars represent SEM. ***P < 0.001, Student's t-test. Abbreviations: AP, Action potential; +/Y, wild-type male; m/Y, mutant male; +/+, wild-type female; +/m, heterozygous female; m/m, mutant female.
