Morphological differentiation of cultured Purkinje cells in the absence (CONTROL) or presence of MPEP or CPCCOEt. Here, the effects of 30 μmMPEP and 30 μm CPCCOEt are illustrated. Similar effects are seen with 1 or 10 μm CPCCOEt and 3 μmMPEP (data not shown). Drugs were administered between 3 and 6 (6 DIV), 6 and 9 (9 DIV), 9 and 13 (13 DIV), or 13 and 17 (17 DIV) DIV, and Purkinje cells were visualized at the indicated DIV, by immunostaining with an anti-calbindin antibody. Representative drawings of several Purkinje cells (left top side) were traced from microphotographs (right bottom side of each panel). Similar data were obtained in three experiments from different culture preparations (n = 3–4). Scale bar, 50 μm.