Neurodegenerative changes in the brainstem and olfactory bulb in people older than 50 years old: a descriptive study / Alterações neurodegenerativas no tronco cerebral e bulbo olfatório em indivíduos acima de 50 anos: um estudo descritivo

With the increase in life expectancy in Brazil, concerns have grown about the most prevalent diseases in elderly people. Among these diseases are neurodegenerative diseases, such as Alzheimer’s and Parkinson’s diseases. Protein deposits related to the development of these diseases can pre-date the symptomatic phases by years. The tau protein is particularly interesting: it might be found in the brainstem and olfactory bulb long before it reaches the limbic cortex, at which point symptoms occur. Of the 14 brains collected in this study, the tau protein was found in the brainstems of 10 (71.42%) and in olfactory bulbs of 3 out 11. Of the 7 individuals who had a final diagnosis of Alzheimer’s disease (AD), 6 presented tau deposits in some region of the brainstem. Our data support the idea of the presence of tau protein in the brainstem and olfactory bulb in the earliest stages of AD.

Com o aumento da expectativa de vida no Brasil e no mundo, crescem as preocupações com as doenças mais prevalentes entre os idosos, dentre elas as doenças neurodegenerativas (DN) como a doença de Alzheimer (DA) e a doença de Parkinson (DP). Sabe-se que os depósitos proteicos relacionados com o desenvolvimento destas doenças podem preceder a fase sintomática em anos. A proteína tau é de particular interesse, uma vez que parece ser encontrada no tronco encefálico e bulbo olfatório muito antes de atingir o córtex límbico, quando ocorrem os primeiros sintomas. Dos 14 encéfalos coletados neste estudo, a proteína tau foi encontrada, no tronco encefálico, em 10 (71,42%) e no bulbo olfatório em 3 de 11. Dos 7 indivíduos que tiveram diagnóstico final de DA, todos apresentavam depósitos de tau em alguma região do tronco encefálico. Nossos dados estão de acordo com a literatura mais recente, que tem confirmado a presença de proteína tau no tronco encefálico e bulbo olfatório nos estágios mais precoces da DA.

Correlation between ANP concentrations in atria, plasma and cerebral structures and sodium chloride preference in Wistar rats

We determined whether ANP (atrial natriuretic peptide) concentrations, measured by radioimmunoassay, in the ANPergic cerebral regions involved in regulation of sodium intake and excretion and pituitary gland correlated with differences in sodium preference among 40 Wistar male rats (l80-220 g). Sodium preference was measured as mean spontaneous ingestion of 1.5 per cent NaCl solution during a test period of 12 days. The relevant tissues included the olfactory bulb (OB), the posterior and anterior lobes of the pituitary gland (PP and AP, respectively), the median eminence (ME), the medial basal hypothalamus (MBH), and the region anteroventral to the third ventricle (AV3V). We also measured ANP contens in the right (RA) and left atrium (LA) and plasma. The concentrations of ANP in the OB and the AP were correlated with sodium ingestion during the preceding 24 h, since an increase of ANP in these structures was associated with a reduced ingestion and vice-versa (OB: r = -0.3649, P<0.05; AP: r = -0.3291, P<0.05). Moreover, the AP exhibited correlation between ANP concentration and mean NaCl intake (r = -0.4165, P<0.05), but this was not the case for the OB (r = 0.2422. This suggests that differences in sodium preference among individu male rats can be related to variations of AP ANP level. Earlier studies indicated that the OB is involved in the control of NaCl ingestion. Our data suggest that the OB ANP level may play a role mainly in day-today variations of sodium ingestion in the individual rat.