Methods for stimulating nervous system regeneration and repair by regulating arginase I and polyamine synthesis

A method for determining whether neurite outgrowth from a particular type of neuron at a particular age is stimulated or inhibited in the presence of MAG and an arginase modulatory agent, the method comprises the steps of:

• a) culturing a first sample of a selected neuronal cell type on a growth-permissive substrate comprising MAG;
• b) culturing a second sample of the selected neuronal cell type on a growth-permissive substrate comprising MAG and at least one added arginase modulatory agent;
• and
• c) comparing the relative amount of neurite growth in the cultured cells of a) and b);
• wherein when the relative growth of neurites in the cultured cells of b) is greater than in a), neurite outgrowth from the selected neuronal cell type is stimulated by the arginase modulatory agent in the presence of MAG;
• and when the relative growth of neurites in the cultured cells of b) is less than in a), neurite outgrowth from the selected neuronal cell type is inhibited by the arginase modulatory agent in the presence of MAG.

A method for determining whether neurite outgrowth from a particular type of neuron at a particular age is stimulated or inhibited in the presence of myelin and an arginase modulatory agent, the method comprises the steps of:

• a) culturing a first sample of a selected neuronal cell type on a growth-permissive substrate comprising purified myelin;
• b) culturing a second sample of the selected neuronal cell type on a growth-permissive substrate comprising purified myelin and at least one added arginase modulatory agent;
• and
• c) comparing the relative amount of neurite growth in the cultured cells of a) and b);
• wherein when the relative growth of neurites in the cultured cells of b) is greater than in a), neurite outgrowth from the selected neuronal cell type is stimulated by the arginase modulatory agent in the presence of myelin;
• and when the relative growth of neurites in the cultured cells of b) is less than in a), neurite outgrowth from the selected neuronal cell type is inhibited by the arginase modulatory agent in the presence of myelin.