(Top panel, a) Immunofluorescence analysis of histologic cryosections of seminiferous tubules cultured for 12 h and processed by TUNEL. 1. control (Bar 20x); 2. MAA (Bar 40x); 3. MAA plus ω-agatoxin (Bar 20x). (Lower panel, b) Quantitative analysis by flow cytometry of testicular cell population prepared from seminiferous tubules cultured for 12 h. Bar represents apoptosis levels determined by TUNEL (p < 0.001). Data are expressed as mean +/- SEM of three independent experiments. 1. control; 2. MAA; 3. MAA plus ω-agatoxin.