Monoamine Oxidase Inhibition and Recovery in the Mouse Brain at Various Ages after Birth

Mice between the ages of 1 day postpartum and adulthood were exposed to the monoamine oxidase inhibitors tranylcypromine and pargyline. The mice were killed at seven different times following drug injection and assayed in vitro for monoamine oxidase activity in four brain regions. Inhibition and recovery of monoamine oxidase activity varied by age, and with the two inhibitors used. During the early maturational period, the potential for new monoamine oxidase synthesis was greater than normal maturational patterns of increase would suggest; and during later maturation either the proportions of various monoamine oxidase forms or their rates of synthesis are different.