Nervous System of Periplaneta americana Cockroach as a Model in Toxinological Studies: A Short Historical and Actual View
Figure 3
The effects of beta group of scorpion toxins on axonal bioelectrical activity. (a) The effect of Bj-xtrIT—a recombinant excitatory anti-insect toxin from Buthus judaicus scorpion: (A) control action potential; (B) action potential recorded from the same axon in 10 min of toxin action (10−7 M)—note much lower threshold (th) for action potential generation and a slight membrane depolarization; (C) repetitive activity evoked after artificial repolarization of axonal membrane and stimulation with single, short (0.5 ms) current pulse; (D) long duration, high frequency repetitive activity observed after the artificial membrane hyperpolarization to −80 mV—activity was evoked by a single, short stimulation. (b) Bigger and prolonged sodium current recorded after 10 min of Bj-xtrIT presence (tx, 10−7 M) compared to control (c); currents were elicited with voltage pulses from HP = −70 mV to −30 and −20 mV. (c) Axonal activity modified by Lqh IT2 (10−6 M)—anti-insect depressant toxin. (A) control action potential and (B) the progressive decrease of its amplitude together with the membrane depolarization induced by toxin; (C) block of action potential generation observed after 15 min of toxin action.
