Attenuation of fear-like response by escitalopram treatment after electrical stimulation of the midbrain dorsolateral periaqueductal gray

Electrical stimulation of the dorsolateral periaqueductal gray (dlPAG) has frequently been shown to induce escape and freezing/decreased locomotion responses which mimic panic- and fear-like behaviour. In the present study we tested whether such spontaneous fear-like behaviour could be observed in an open-field test 12 h after dlPAG stimulation. Further, we tested whether this fear-like behaviour could be attenuated by acute or chronic administration of buspirone and escitalopram. Our data demonstrate for the first time that animals showed fear-like behaviour 12 h after dlPAG stimulation, which may possibly reflect panic disorder with anticipatory anxiety/agoraphobic symptoms. Acute and chronic escitalopram, but not buspirone, treatment attenuated the fear-related behaviour. Besides, our data also showed that the stimulation intensities to evoke an escape reaction, a panicogenic response, were significantly higher after chronic buspirone and escitalopram treatment. These results suggest that the fear-like response, which was observed 12 h after dlPAG stimulation, could be considered as a relevant animal model for panic disorder with anticipatory anxiety/agoraphobic symptoms.