４８、As people grow older, an enzyme known as PEP increasingly breaks down the neuropeptide chemicals involved in learning and memory. But now, researchers have found compounds that prevent PEP from breaking neuropeptides apart. In tests, these compounds almost completely restored lost memory in rats. The use of these compounds should be extended to students who have poor memory and difficulty in concentrating—and therefore serious problems in school performance. Science finally has a solution for problems neither parents nor teachers could solve.