4-Aminobutyraldehyde as a precursor convertible to gamma-aminobutyric acid in vivo.

It was found that 4-aminobutyraldehyde (ABAL) is a precursor convertible to gamma-aminobutyric acid (GABA) in vivo. [2,3-3H]ABAL was synthesized from [2,3-3H]putrescine. After the subcutaneous administration of [3H]ABAL at the dose of 1 mumol/g body weight, [3H]GABA was produced in the mouse brain in an amount of about 350 nmol/g brain in 10 min. After oral administration of [3H]ABAL at the dose of 2 mumol/g body weight, [3H]GABA was also produced in the brain in an amount of about 530 nmol/g brain in 30 min. It seems that peripherally administered ABAL penetrates the blood-brain barrier into the central nervous system and is rapidly metabolized to GABA in the brain.