Skip to Content
Merck
  • The aggression and behavioral abnormalities associated with monoamine oxidase A deficiency are rescued by acute inhibition of serotonin reuptake.

The aggression and behavioral abnormalities associated with monoamine oxidase A deficiency are rescued by acute inhibition of serotonin reuptake.

Journal of psychiatric research (2014-06-03)
Sean C Godar, Marco Bortolato, M Paola Castelli, Alberto Casti, Angelo Casu, Kevin Chen, M Grazia Ennas, Simone Tambaro, Jean C Shih
ABSTRACT

The termination of serotonin (5-hydroxytryptamine, 5-HT) neurotransmission is regulated by its uptake by the 5-HT transporter (5-HTT), as well as its degradation by monoamine oxidase (MAO)-A. MAO-A deficiency results in a wide set of behavioral alterations, including perseverative behaviors and social deficits. These anomalies are likely related to 5-HTergic homeostatic imbalances; however, the role of 5-HTT in these abnormalities remains unclear. To ascertain the role of 5-HTT in the behavioral anomalies associated to MAO-A deficiency, we tested the behavioral effects of its blocker fluoxetine on perseverative, social and aggressive behaviors in transgenic animals with hypomorphic or null-allele MAO-A mutations. Acute treatment with the 5-HTT blocker fluoxetine (10 mg/kg, i.p.) reduced aggressive behavior in MAO-A knockout (KO) mice and social deficits in hypomorphic MAO-A(Neo) mice. Furthermore, this treatment also reduced perseverative responses (including marble burying and water mist-induced grooming) in both MAO-A mutant genotypes. Both MAO-A mutant lines displayed significant reductions in 5-HTT expression across the prefrontal cortex, amygdala and striatum, as quantified by immunohistochemical detection; however, the down-regulation of 5-HTT in MAO-A(Neo) mice was more pervasive and widespread than in their KO counterparts, possibly indicating a greater ability of the hypomorphic line to enact compensatory mechanisms with respect to 5-HT homeostasis. Collectively, these findings suggest that the behavioral deficits associated with low MAO-A activity may reflect developmental alterations of 5-HTT within 5-HTergic neurons. Furthermore, the translational implications of our results highlight 5-HT reuptake inhibition as an interesting approach for the control of aggressive outbursts in MAO-A deficient individuals.

MATERIALS
Product Number
Brand
Product Description

Supelco
Fluoxetine Hydrochloride, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Fluoxetine hydrochloride, solid
USP
Fluoxetine hydrochloride, United States Pharmacopeia (USP) Reference Standard
Supelco
Fluoxetine hydrochloride, VETRANAL®, analytical standard