No abstract

Serotonin deficiency induced in newborn mice and maintained to adulthoodresulted in reduced ability to learn a maze. The serotonin deficiency was produced by overloading with phenylalanine plus tyrosine (to cause phenylketonuria), by feeding of reserpine, and by feeding of chlorpro mazine from birth to maturity.

Excess of cerebral serotonin decreased maze-learning ability of adult mice; deficiency of serotonin and catechol amines increased it slightly.

Mice made phenylketonuric from birth until maturity by continuous administration of phenylalanine plus tyrosine had a subnormal maze-learning ability which was largely prevented when serotonin congeners such as melatonin or 5-hydroxytryptophan were administered continuously from birth to maturity. These results were interpreted to mean that the mental failure of experimental phenylketonuria is attributable to the serotonin deficiency imposed by it in infancy.

No abstract