Skip to main content
. 2019 May 24;17(5):306. doi: 10.3390/md17050306

Figure 4.

Figure 4

PnTX-A blockade of nerve-evoked isometric twitch tension without modification of directly elicited twitch and tetanus tension on isolated mouse EDL muscles. (a) (a1) Single twitch tension recording under control conditions, (a2) Marked reduction in twitch amplitude during the action of PnTX-A (54 nM), (a3) Reversal of the blockade produced by PnTX-A by 3,4-DAP (100 µM). (a4,a5) Twitch and tetanus responses evoked by direct muscle stimulation at 0.03 and 80 HZ, respectively in an EDL muscle in which nerve-evoked contractions were completely blocked by 56 nM PnTX-A. (b,c) Time course and concentration dependence of PnTX-A and PnTX G effects on nerve-evoked twitch responses, and the reversal by wash-out and 3,4-DAP (100 µM). After an equilibration period of 20 min PnTXs were applied at time 0. In (b) the wash-out of PnTX-A (84 nM), and the fast reversal of PnTX-A action by 3,4-DAP are shown. Note the slower onset kinetics of PnTX-G (c) as compared to PnTX-A (b) on nerve-evoked muscle contraction. Each value is expressed relatively to that obtained before addition of PnTXs.