Modulation of stress consequences by hippocampal monoaminergic, glutamatergic and nitrergic neurotransmitter systems.
Several findings relate the hippocampal formation to the behavioural consequences of stress. It contains a high concentration of corticoid receptors and undergoes plastic modifications, including decreased neurogenesis and cellular remodelling, following stress exposure. Various major neurotransmitter systems in the hippocampus are involved in these effects. Serotonin (5-HT) seems to exert a protective role in the hippocampus and attenuates the behavioural consequences of stress by activating 5-HT1A receptors in this structure. These effects may mediate the therapeutic actions of several antidepressants. The role of noradrenaline is less clear and possibly depends on the specific hippocampal region (dorsal vs. ventral). The deleterious modifications induced in the hippocampus by stress might involve a decrease in neurotrophic factors such as brain derived neurotrophic factor (BDNF) following glutamate N-methyl-D-aspartate (NMDA) receptor activation. In addition to glutamate, nitric oxide (NO) could also be related to these effects. Systemic and intra-hippocampal administration of nitric oxide synthase (NOS) inhibitors attenuates stress-induced behavioural consequences. The challenge for the future will be to integrate results related to these different neurotransmitter systems in a unifying theory about the role of the hippocampus in mood regulation, depressive disorder and antidepressant effects.
Joca
Sâmia Regiane Lourenço
SR
Department of Pharmacology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
Ferreira
Frederico Rogério
FR
Guimarães
Francisco Silveira
FS
D000223:Adaptation, Psychological; D000339:Affect; D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology / Q000627:therapeutic use; D015306:Biogenic Monoamines / Q000378:metabolism*; D003863:Depression / Q000188:drug therapy / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D026602:Nitrergic Neurons / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D009569:Nitric Oxide / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism; D013315:Stress, Psychological / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology
D000928:Antidepressive Agents; D015306:Biogenic Monoamines; D009569:Nitric Oxide; D012701:Serotonin; D018698:Glutamic Acid; D004298:Dopamine; D009638:Norepinephrine