A crucial brain route that mediates symptoms of panic disorder: Study

Researchers at Salk have made significant progress in understanding panic disorder by discovering a brain circuit that plays a part in regulating the symptoms. Notably, this circuit involves neurons that communicate using a neuropeptide called PACAP. The findings indicate that both PACAP and the neurons responsible for its receptor could serve as potential targets for more effective treatments for panic disorder.

This research goes some distance in charting the brain's mechanism behind panic attacks, which often include extreme fear, sweaty palms, breathlessness, and rapid heart rate. The results, published in Nature Neuroscience, shift previous assumptions about the origins of panic attacks.

Earlier, it was believed that the amygdala, the part of the brain associated with fear, was primarily responsible. However, even individuals with damaged amygdalas can experience these episodes, prompting researchers to alter their direction in understanding the condition. The investigation led them to a specific brain circuit outside the amygdala associated with panic disorder.

The researchers' focus was on the lateral parabrachial nucleus (PBL) in the pons, known as the brain's alarm center. Additionally, the PBL also handles breathing, heart rate, and body temperature. The PBL was found to produce PACAP, which is known for regulating stress responses. To further verify these findings, the team used a mouse model.

The researchers discovered a unique link between PACAP-expressing neurons and panic disorder during panic attacks in mice. These neurons, when activated, release PACAP to the dorsal raphe, where PACAP receptors are found. The PACAP thus sent triggers these receptors, leading to panic-related behavioral and physical symptoms.

Moreover, the researchers concluded that inhibiting PACAP signaling can reduce panic-related symptoms. The study highlights the fundamental differences between panic disorder and other forms of anxiety, emphasizing the importance of appropriate treatments. The researchers look forward to mapping more specifically the brain's response to panic disorder, particularly focusing on PACAP and its associated neurons.