Microdialysis of dichlorvos was initiated at time zero. Data represent an average of all experimental (dichlorvos) animals (open circles, n=7) and control (vehicle only) animals (filled circles, n=6). All respiratory measurements decreased significantly post exposure (p<0.0001, repeated measures ANOVA). The respiratory rate (A) and volume of expired gas (B) were significantly different, comparing dichlorvos with vehicle alone (p<0.04, ANOVA). There was no significant difference in minute ventilation (C) between groups (p=0.12, ANOVA).