Fig. 12. Summarized effects of putative transmitters on the number of locomotor arrests per minute during exposure of free swimming larvae to the following compounds: serotonin (from 10^-4 mol l^-1 to 10^-6 mol l^-1), dopamine and norepineprhine (from 10^-4 mol l^-1 to 10^-6 mol l^-1), FMRFamide and Leu-enkephalin (from 10^-4 mol l^-1 to 10^-6 mol l^-1). Asterisks indicate significant difference when compared with the control group (P<0.05).