Quick Answer. The function of a synaptic knob is to change the action potential that is carried by axons into a chemical message. The chemical message then interacts with the recipient neuron or effector. This process is called synaptic transmission.
Over-the-counter (OTC) medicines that are recommended for head or pubic lice include: 1  Permethrin creme rinse 1% (such as Nix), which is a common first choice for treating head lice. 2  Shampoos containing pyrethrins and piperonyl butoxide (such as Rid), which are left on the hair for 10 minutes and then rinsed out.
Medicine containing pyrethrins is used to treat head, body, and pubic lice infections. This medicine is absorbed by the lice and destroys them by acting on their nervous systems. It does not affect humans in this way. The piperonyl butoxide is included to make the pyrethrins more effective in killing the lice.