Serotonergic system hippocampus

TPH activity was dramatically decreased in the hippocampus to 5 or 1 percent of control, respectively, with 0.25 or 0.5 moles of the metabolite. The content of 5-HT and 5-HIAA in the hippocampus was also decreased. The striatal serotonergic system was more resistant to the effects of THA. In this structure, TPH activity was decreased to 74 percent and 81 percent of control 1 week after a single injection of 0.25 or 0.5 mol of THA, while the concentration of 5-HT and 5-HIAA remained unaltered. THA administration dramatically decreased all dopaminergic parameters in the striatum. 

Since there are both noradrenergic projections to the hippocampus from the locus coeruleus and serotonergic projections to the hippocampus from the raphe, it is possible that dysregulation of these projections may account for neurophysiological abnormalities hypothesized to occur in panic attacks. Changing the outputs of these monoamine neurotransmitter systems to the hippocampus may also explain the therapeutic actions of various antidepressants that reduce panic attacks (see Figs. 5—26 and 5—54). 

Marshall DL, Redfern PH, Wonnacott S (1997) Presynaptic nicotinic modulation of dopamine release in the three ascending pathways studied by in vivo microdialysis comparison of naive and chronic nicotine-treated rats. J Neurochem 68 1511-19 Mongeau R, Blier P, De Montigny C (1997) The serotonergic and noradrenergic systems of the hippocampus their interactions and the effects of antidepressant treatments. Brain Res Rev 23 145-95... 

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