Novel effect of α-lactalbumin on the yohimbine-induced hot flush increase of the tail skin temperature in ovariectomized rats.

ABSTRACT

5-Hydroxytryptamine (5-HT) and noradrenaline have been thought to play important roles in the mechanism of hot flush. Then, to clarify the relation between serotonergic and adrenergic nervous systems on the mechanism of hot flush, the effect of paroxetine, 5-HT reuptake inhibitor (SSRI) was evaluated on the yohimbine-induced hot flush increase of tail skin temperature in ovariectomized female rats. Yohimbine (adrenaline α2 antagonist) significantly increased the tail skin temperature in course of time. Clonidine (adrenaline α2 agonist) significantly attenuated this effect. Paroxetine also significantly inhibited the increase of tail skin temperature by yohimbine. α-Lactalbumin having SSRI activity in vitro study also significantly inhibited the increase of tail skin temperature, but not significantly decreased the initial temperature. This difference may explain the different mechanism between paroxetine (SSRI) and α-lactalbumin, suggesting new mechanism of hot flush.