C1 induces mitochondrial swelling via induction of the MPT pore, whereas C2 has no effect on the pore. Large amplitude mitochondrial swelling was determined spectroscopically by monitoring the loss of absorbance at 540 nm as described in Materials and Methods. Mitochondria (0.5 mg) were treated with (A) 200 μmol/L DEPC as a positive control to induce mitochondrial swelling or (B) C1 (100 μg) or (C) C2 (100 μg) in the absence or presence of MPT pore inhibitor CsA (10 μmol/L).