Figure 1. Upregulated LTCC expression in APP−/− striatal tissue and enhanced ICa2+ in APP−/− striatal cultures. A, Representative immunoblots of tissue extracts from striatum of 3-week-old APP−/− (−/−) and WT (+/+) littermates. The blots were probed with anti-α1C, α1A and α1B subunit antibodies representing LTCC, P/QTCC and NTCC, respectively. α-Tubulin was used as loading control. B, Quantification of the immunoblots revealed a significant increase in LTCC expression, but not P/QTCC or NTCC in APP−/− mice. Each value represents the mean ± SEM of six samples/genotype. *p < 0.05. C, Plot of peak current density vs voltage in WT (N = 24) and APP−/− (N = 39) striatal neurons and example traces of whole-cell Ca2+ currents elicited by a series of depolarizing steps in WT and APP−/− striatal neurons. D, Plot of peak current density vs test pulse voltage under control conditions (WT, N = 9; APP−/−, N = 21), or in the presence of LTCC blocker (WT, N = 9; APP−/−, N = 21), LTCC blocker + P/QTCC blocker (WT, N = 9; APP−/−, N = 18), or LTCC blocker + P/QTCC blocker + NTCC blocker (WT, N = 8; APP−/−, N = 14). E, Bar graphs illustrate the blockade of peak current exerted by L-, N-, and P/Q-blockers, respectively, in WT and APP−/− striatal cultures. L-blocker-sensitive components increased significantly in APP−/− striatal cultures compared with WT controls. Error bars indicate SEM. **p < 0.01. Calibration: 100 pA/100 ms.