Dimefluthrin

Danio rerio larvae (5 days post-fertilization larvae)^[1]

0.2, 0.4, 0.8 μg/mL

waterborne; continuous; 72 h (solution replacement every 24 h)

Caused concentration-dependent inhibition of olfactory bulb, telencephalon, mesencephalon, medulla oblongata, optic parietal region, and hindbrain neuron development.
Reduced relative length of CNS axon tracts by ~50% at 0.4 μg/mL (P < 0.01) and ~90% at 0.8 μg/mL (P < 0.01).
Widened hindbone spacing in a concentration-dependent manner, with a ~3-fold increase at 0.8 μg/mL (P < 0.01).
Reduced relative fluorescence intensity of overall brain vasculature by ~20% at 0.2 μg/mL (P < 0.05), ~50% at 0.4 μg/mL (P < 0.01), and ~80% at 0.8 μg/mL (P < 0.01).
Widened intersegmental vessel spacing by ~70% at 0.8 μg/mL (P < 0.01), with no significant changes at 0.2 or 0.4 μg/mL.
Reduced relative fluorescence intensity of cerebral veins by ~50% at 0.4 μg/mL (P < 0.01) and ~70% at 0.8 μg/mL (P < 0.01), with no significant change at 0.2 μg/mL.
Caused disorganized, sparse brain cell distribution with vacuolization, blurred brain structure borders, and tail muscle cell vacuolization at all tested doses.
Induced coin-shaped skeletal fiber arrangements in the notochord at 0.8 μg/mL.
Decreased acetylcholinesterase activity in a concentration-dependent manner, with significant decreases at all tested doses (P < 0.01).
Dysregulated expression of neurodevelopment-related genes, including upregulation of elavl3 and downregulation of syn2a, dat, mao, and dr1 in a concentration-dependent manner.
Upregulated comt and th gene expression by ~2.2-fold and ~2.8-fold, respectively, at 0.8 μg/mL (P < 0.01).
Induced concentration-dependent suppression of locomotor activity, with total swimming distance reduced by ~30% at 0.2 μg/mL, ~50% at 0.4 μg/mL (P < 0.01), and ~80% at 0.8 μg/mL (P < 0.01).
Reduced swimming speed and acceleration in a concentration-dependent manner.
Restored total swimming distance, speed, and acceleration to levels near those of untreated controls when co-exposed with Bromocriptine for dimefluthrin-induced locomotor suppression.