Knowledge center. Amphetamines are drugs which stimulate the CNS (central nervous system) - they are psychostimulant drugs-when overused they can be psychologically and physically addictive. As well as giving the user an enhanced feeling of wakefulness and focus, they also reduce appetite.mphetamines stimulate the central nervous system and the sympathetic part of the peripheral nervous system. Experts say that amphetamines enhance the synaptic activity of three neurotransmitters-dopamine, serotonin and norepinephrine.
Propagation of action potential along myelinated nerve fiber. Saltatory conduction (from the Latin saltare, to hop or leap) is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials.n addition to increasing the speed of the nerve impulse, the myelin sheath helps in reducing energy expenditure over the axon membrane as a whole, because the amount of sodium and potassium ions that need to be pumped to bring the concentrations back to the resting state following each action potential is decreased.
The myelin sheath around most vertebrate axons provides a layer of insulation that prevents the loss of the electrical signal from an action potential. Myelin is lipid rich substance that does not conduct electricity well.ecause of the insulation provided by the myelin, action potentials can travel much more rapidly down myelinated axons than down unmyelinated axons. Myelin also isolates axons from one another in the white matter of the brain preventing the short-circuiting of nerve signals in the central nervous system.