Brain switch turns 'on' when danger hits, 'off' when threat passes

The brain apparently has its own switch that controls production of cortisol from adrenal glands depending on stress levels, researchers in Israel and France have found through looking at zebra fish. Details are published in the journal Neuron. A protein called Otp steps in when the brain senses danger or trouble to activate genes causing the release of corticotropin releasing hormone (CRH). What's new here is scientists now know that the same protein regulates production of two different receptors on the surface of neurons that control how CRH production signals are both received and relayed. Both receptors are variations of PAC1: One is shorter and creates the "on" switch; the other is longer and handles turning "off" the production. When scientists blocked the longer variation, the zebra fish appear to behave like they were anxious. The same process in mice generated a similar response. The idea is that this process can become defective and may lead to issues like post-traumatic stress disorder or depression. Making it work properly may help treat those and other stress-related conditions. Release