The Scutellaria Flavone, Oroxylin A, Improves Attention-Deficit/Hyperactivity Disorder Related Behaviors in Spontaneously Hypertensive Rats

Abstract

Oroxylin A is a flavonoid isolated from Scutellaria baicalensis, which is one of the most important medicinal herbs in traditional Korean medicine. In this study, we investigated the psychopharmacological activities of oroxylin A using the open field, rota-rod, balanced wire and plus-maze tests in Spontaneously Hypertensive Rats (SHR) and Wistar Kyoto Rats (WKY). Oroxylin A reduced hyperactivity in SHR (ADHD animal model) although it tended to increase locomotor activity in WKY. Methylphenidate did not reduce hyperactivity. Oroxylin A alleviated impulsive behaviors such as rearing, the percentage of moving time to the central area and the tendency to move into an unstable condition (open area in elevated plus-maze). Methylphenidate also reduced the percentage of staying time in the central area and the tendency to move into an unstable condition. Both oroxylin A and methylphenidate enhanced motor attention in SHR and WKY. Oroxylin A antagonized the muscimol (<TEX>$GABA_A$</TEX> receptor agonist)-induced <TEX>$Cl^-$</TEX>current and its action was similar to that of bicuculline (<TEX>$GABA_A$</TEX> receptor antagonist). The effects of oroxylin A may be caused by the antagonism at the <TEX>$GABA_A$</TEX> receptor. Thus, oroxylin A may be a candidate of drug for treatment of ADHD.