Limbic mechanisms of anxiolytics acting on 5-HT receptors

The role of brain serotonergic system innervating hippocampus and nucleus accumbens in the anxiolytic-like action of the 5-HT1A receptor agonists and 5-HT3 receptor antagonists, is discussed. The data on the effects of intrastructural microinjections of selective serotonergic agonists and antagonists in the Vogel and open field (neophobic reaction) tests are described and critically reviewed. It is concluded that both postsynaptic inhibition of the temporal lobe function (the hippocampus), and attenuation of the cell body firing of the raphe neurons appears to be important elements of anti-anxiety action of benzodiazepines and 5-HT1A receptor antagonists. Thus, it is hypothesized that this dual mechanism of the 5-HT1A receptor agonists and the 5-HT3 receptor antagonists action cooperates synergistically in the processing of emotional functions.