Comparison of the effects of selected aminoglycoside antibiotics on motor behaviors in mice.

Aminoglycoside antibiotics (AGs) can cause neuromuscular blockade and paralysis of skeletal muscles. To compare the paralytic effects of selected AGs on some motor behaviors in mice, 24 male mice were divided into four groups. Each group was given one of AGs (gentamicin, dihydro-streptomycin, apramycin and amikacin) at incremental doses that increased half-logarithmically compared to the therapeutic dose (16.00 mg kg). Motor behavioral tests included open field test, inclined plane, horizontal bars, static rods, parallel bars and rotarod. Finally, the data were analyzed using descriptive and analytical statistics. Gentamicin and dihydrostreptomycin at 32.00 times of the therapeutic dose produced complete paralysis of the limbs, respiratory arrest, and even death in some animals. However, apramycin and amikacin did not show significant effects on skeletal muscle and motor behaviors at 32.00 times of the therapeutic dose. After administration of apramycin at 100 times of the therapeutic dose, four out of six mice (66.67%) died from respiratory depression. Amikacin at this dose did not cause animal death, although it caused some changes in motor behaviors with a significant difference in comparison with control values. Gentamicin demonstrated significantly more potent effects on motor behaviors compared to the other AGs. Overall, the order of potency was gentamicin > dihydrostreptomycin > apramycin > amikacin. High doses of AGs could impair the skeletal muscle function and disrupt motor behaviors in mice. Furthermore, the paralytic potency of selected AGs on skeletal muscle was significantly different.