Abrain chemical that plays a role in brain metabolism, is elevated in individuals with panic disorder.

Cortisol, a brain chemical that plays a role in brain metabolism, is elevated in individuals with panic disorder.

Explanation:

Cortisol is a hormone that acts as a neurotransmitter in our brain and also plays a key role in our metabolism. Considered by the scientific community as "stress hormone", our body produces in situations of tension to help cope with them. The release of this hormone is controlled by the hypothalamus in response to stressful situations and a low level of glucocorticoids in the blood. It is also well known that high levels of cortisol are present in various pathologies including panic disorder.

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.