Figure 5
(A) Effect of an acute treatment with nilvadipine, amlodipine, nifedipine, nitrendipine and DAPT on brain soluble Aβ levels in Tg PS1/APPsw mice. DAPT (10 mg/kg of body weight), nilvadipine (2 mg/kg), amlodipine (2 mg/kg) and nifedipine (2 mg/kg) were dissolved in 50% DMSO/PBS and administered to Tg PS1/APPsw mice (6-month-old) intraperitoneally for 4 d. Vehicle treated Tg PS1/APPsw mice received an i.p. injection of the vehicle for 4 d. Within 1 h after the last injection, brains and plasma samples were collected. Brain soluble Aβ levels and plasma Aβ levels were quantified by ELISAs. ANOVA reveals statistically significant main effect of the acute treatment with nilvadipine (P < 0.05), nitrendipine (P < 0.01) and DAPT (P < 0.004) on brain Aβ level but no main effect for amlodipine (P = 0.184) and nifedipine (P= 0.36) treatments. Post hoc analysis show statistically significant differences in brain Aβ1−40 levels between control and nilvadipine treated mice (P < 0.05) as well as significant differences between brain Aβ1−42 and Aβ1−40 levels between vehicle and nitrendipine-treated mice (P < 0.01) and between vehicle- and DAPT-treated mice (P < 0.004). (Average brain soluble Aβ1−40 and Aβ1−42 values observed in vehicle-treated mice were respectively 10249.1 and 8770.8 pg/mg of protein). (B) Effect of an acute treatment with nilvadipine, amlodipine, nifedipine, nitrendipine and DAPT on plasma Aβ levels in Tg PS1/APPsw mice. An elevation of plasma Aβ1−40 and Aβ1−42 was observed following nilvadipine and nitrendipine treatments, whereas a decreased plasma Aβ1−42 level was observed following DAPT treatment. ANOVA reveals a statistically significant main effect of the acute treatment with nilvadipine (P < 0.05) and nitrendipine (P < 0.01) on plasma Aβ1−40 level and significant main effect of nilvadipine (P < 0.05), nitrendipine (P < 0.01) and DAPT (P < 0.04) on plasma Aβ1−42, but no main effect for amlodipine and nifedipine treatments (P > 0.05). Post hoc comparisons shows significant differences in plasma Aβ1−40 values between vehicle, nilvadipine and nitrendipine treated mice (P < 0.05) and significant differences in plasma Aβ1−42 values between vehicle, nilvadipine, nitrendipine and DAPT treatments (P < 0.05). (Average plasma Aβ1−40 and Aβ1−42 values observed in vehicle treated mice were respectively 1384.9 and 293.9 pg/mL.)