Protocol

Aim
To demonstrate the effects of curare on the twitch contraction and the compound nerve action potential.

The sciatic nerve is stimulated with single supramaximal stimuli (frequency 0.1 Hz) before and after the dropwise application of a solution of curare (0.01 mM) to the nerve and muscle.

When you have observed the effect of curare on the muscle response evoked by stimulation of the nerve, select "stimulate muscle directly" to see whether the muscle will respond to direct electrical stimulation in the presence of curare.

Task
Measure the amplitude of the contractile response just before, and every 10 seconds after, the application of the curare. Plot a graph of muscle twitch amplitude against time.

Then try answering the questions.