Details

Autor(en) / Beteiligte

• Costa, Joana Bárbara Cascais da

Titel

Efeito dos psicoestimulantes na neurogénese do cérebro adulto

Ort / Verlag

ProQuest Dissertations & Theses

Erscheinungsjahr

2012

Link zum Volltext

• ProQuest

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• The adult brain is well coordinated and endowed with plasticity. Thus, it has the capacity to adapt to morphological and physiological changes, as well as those related with environment, which can affect several nerve cells changing their structure and function. Neurogenesis is, indeed, a phenomenon responsible for brain adaptation since it involves the constant production and introduction of new cells in a pre-existing and functional neural network. The neurogenic process is accompanied by synaptogenesis, and both are regulated by neurotransmitters, hormones and growth factors. Indeed, the adult brain neurogenesis occurs mainly in two brain areas: the subgranular zone (SGZ), located in the dentate gyrus of the hippocampus, commonly related with cognitive processes; and the subventricular zone (SVZ) that lies along the lateral ventricles and is responsible for the integration of neurons in the olfactory bulb. However, neurogenesis in the adulthood is an unprofitable process because only half of the newly formed cells that migrate and differentiate will survive for more than one month. Among several drugs of abuse, the psychostimulants have several effects such as in-creased motor activity, decreased fatigue, euphoria, as well as sympathomimetic effects. Overall, psychostimulant drugs have a negative impact in neurogenesis as they reduce cell proliferation and integration of new neurons in the pre-existing neural network. This type of drug is also associated with behavioral changes, including schizophrenic-like behavior and cognitive deficits. Although the effect of psychostimulants on neurogenesis depends on several conditions like the dose and frequency of consumption, there are studies showing that even a single acute consumption can impair neurogenesis. The use of psychostimulants can lead to addiction, which is a brain disease with a high social impact. On the other hand, some of these drugs are prescribed in clinical practice with a positive impact in the pathogenesis of disease and its morbidity. Thus, in both situations, and knowing that neurogenesis is an ongoing process with a key role in brain function, is crucial to understand how psychostimulants affect the neurogenic process on the adult brain