The effect of cocaine on spindle morphology in mouse oocytes was inves
tigated. Oocytes were exposed to 10, 100 and 1000 mu g cocaine/ml and
cultured for 20 hr to the metaphase II equivalent stage. Spindles were
visualized in whole-mount preparations by indirect immunofluorescence
staining for tubulin. Concentrations of 10 and 100 mu g cocaine/ml ha
d no significant effect on oocyte maturation. Cocaine at a concentrati
on of 10 mu g/ml also had no discernible effect on spindle morphology
but exposure to 100 mu g/ml resulted in a significant increase in the
frequency of defective spindles (44 +/- 7% compared with 12 +/- 2% in
controls). Exposure to 1000 mu g cocaine/ml blocked development at the
metaphase I stage. The abnormal spindles were characterized by barrel
shapes and asymmetric spindle halves containing wavy or branched spin
dle fibres. Chromosome misalignment was also observed in some cases. S
pindle-active agents are known to cause chromosome malsegregation and
the results of this study suggest that cocaine may have the potential
to cause aneuploidy. Copyright (C) 1996 Elsevier Science Ltd