Electrical stimulation of the dorsolateral
periaqueductal gray (dlPAG) has been shown to induce
escape and freezing responses which mimic the panic- and
fear-like behaviour. In the present study, we tested the
hypothesis whether the freezing behaviour could be
attenuated by acute and chronic administration of
escitalopram and buspirone. Additionally, the levels of
blood corticosterone were measured in the different
experimental conditions. Our results demonstrated that
escitalopram treatment was effective in attenuating the
stimulation induced fear when compared to buspirone and
saline treated animals after acute and chronic treatment.
The stimulation amplitudes to evoke escape behaviour
were significantly higher after chronic buspirone and
escitalopram treatment. The levels of blood corticosterone
were increased after stimulation and the open-field testing
conditions when compared to the baseline level. In
conclusion, the current study shows that the escape
reaction generated intrinsically within the dlPAG was
followed by freezing behaviour 12 h later. This fear-like
behaviour was reversed by escitalopram treatment while
buspirone or vehicle treated groups did not attenuate fear
behaviour. Our data also confirm the elevation of blood
corticosterone level during the panic and fear-like
behaviour. Future research of fear should be focused on
the underlying neural mechanism within the dlPAG.