Although less studied, in conditioned fear experiments animals demonstrated an increase in serotonin (5-HT) turnover in different brain areas, with preferential release in mPFC. Serotonin antagonists produce behavioral deficits resembling those seen following inescapable shock. Chronic stress increases cortical 5-HT2 receptor binding and reduces hippocampal 5-HT1A receptor binding. Drugs that enhance serotonin neurotransmission are effective in reversing this behavioral "learned helplessness." Injection of serotonin into the frontal cortex after stress exposure reverses behavioral deficits.

The effect of stress in activating serotonin turnover may stimulate a system that has both anxiogenic and anxiolytic pathways within the forebrain. A primary distinction in the qualitative effects of serotonin may be between the dorsal and median raphe nuclei, the two midbrain nuclei that produce most of the forebrain serotonin. The serotonergic innervation of the amygdala and the hippocampus by the dorsal raphe are believed to mediate anxiogenic effects via 5-HT2 receptors. In contrast, the median raphe innervation of hippocampal 5-HT1A receptors has been hypothesized to facilitate the disconnection of previously learned associations with aversive events or to suppress formation of new associations, thus providing resilience to aversive events.

Free Yourself from Panic Attacks

Free Yourself from Panic Attacks

With all the stresses and strains of modern living, panic attacks are become a common problem for many people. Panic attacks occur when the pressure we are living under starts to creep up and overwhelm us. Often it's a result of running on the treadmill of life and forgetting to watch the signs and symptoms of the effects of excessive stress on our bodies. Thankfully panic attacks are very treatable. Often it is just a matter of learning to recognize the symptoms and learn simple but effective techniques that help you release yourself from the crippling effects a panic attack can bring.

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