Deltamethrin-induced changes in synaptosomal transport of 3H-epinephrine in the squid optic lobes.

In fresh synaptosomal preparation from the squid optic lobe 3H-epinephrine transport was significantly affected by deltamethrin at greater than 10(-9) M. Under the experimental conditions such an effect of deltamethrin manifested as either a reduction (at nondepolarized state) or an increase (at depolarized state) in the final level of 3H-epinephrine accumulated in the synaptosomes. Only a part of such a deltamethrin effect was due to its effect on the sodium channel. The remainder of the deltamethrin effect was strongly influenced by agents or treatments which are known to influence internal Ca2+ concentration, suggesting a possible involvement of Ca2+ regulatory mechanisms in the process of stimulation of transmitter release by deltamethrin.