the sleep promoting effects of factor s can not be duplicated by serotonin , 4-oh-butyrate , butyrolactone , gaba ( gamma-amino butyric acid ) , glutamic acid or 3',5'-cyclic amp when these substances are added to control fluids in concentrations up to 10 times greater than those found in normal c.s.f.5 .
C0439861
substances
C0005889
fluids