Fig. 5.

AT_1A receptors, but not AT_1B or AT₂ receptors, are involved in telmisartan neuroprotection. (A) Angiotensin II receptor gene expression after exposure to glutamate. AT_1A, AT_1B and AT₂ gene expression were determined in rat CGCs after 24 hour exposure to glutamate. (B) CGCs were pre-treated with 1 µM telmisartan (Telm) for 2 h followed by exposure to 100 µM glutamate (Glut) for the indicated time intervals. (C) CGCs were simultaneously exposed to the NMDA receptor antagonist MK-801 (10 µM) and glutamate, and AT_1A gene expression was determined 24 hours later. (D) CGCs were exposed to glutamate and AT₁ receptor expression was determined by the Angiotensin II receptor binding assay, 24 and 48 hours later. (E) CGCs were treated with the AT₂ receptor antagonist PD123319 (PD, 10 µM) or the AT₂ receptor agonist CGP42112A (CGP, 10 µM) for one hour, followed by treatment with vehicle or telmisartan (1 µM) for two hours, followed by exposure to glutamate for 24 hours, followed by determination of LDH activity in the culture supernatant. Data are presented as means ±SEM of three independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001 vs. Control; ^##P < 0.01, ^###P < 0.001 vs. Glutamate.