Brain Aging and Electrophysiological Signaling: Revisiting the Spreading Depression Model

Abstract

As a consequence of worldwide improvement in health care, the aging portion of the human population has increased, now representing a higher proportion of the total population. This fact raises great concern regarding how to age while maintaining good brain function. Very often, alterations in brain electrophysiological signaling are associated with age-dependent functional disorders of the brain. Therefore, animal models suitable for the study of age-related changes in electrical activity of the brain can be very useful. Herein, we review changes in brain electrophysiological features as a function of age by analyzing studies in the rat brain on the phenomenon known as cortical spreading depression (CSD). Alterations in the brain’s capability to generate and propagate CSD may be related to differences in the propensity to develop certain neurological diseases, such as epilepsy, stroke, and migraine, which can biunivocally interact with the aging process. In this review, we revisit ours and others’ previous studies on electrophysiological features of the CSD phenomenon, such as its velocity of propagation and amplitude and duration of its slow negative DC shift, as a function of the animal age, as well as the interaction between age and other factors, such as ethanol consumption, physical exercise, and nutritional status. In addition, we discuss one relatively new feature through which CSD modulates brain signaling: the ability to potentiate the brain’s spontaneous electrical activity. We conclude that the CSD model might importantly contribute to a better understanding of the aging/brain signaling relationship.

Taurine/Pilocarpine Interaction in the Malnourished Rat Brain: A Behavioral, Electrophysiological, and Immunohistochemical Analysis

“…The present study extends the previous observations of our group on the effects of taurine (Francisco and Guedes, 2015) and pilocarpine (Mendes-da-Silva et al, 2018) in rats of a younger age (PND7-27) than our rats (PND35-55). Analyzing such effects at another age might be of importance, regarding the time course of drug actions (Guedes and Abadie-Guedes, 2019). Treatment with taurine and pilocarpine resulted in anxiolytic-like and anxiogenic behavior, respectively.…”

Valeriana officinalis Counteracts Rotenone Effects on Spreading Depression in the Rat Brain in vivo and Protects Against Rotenone Cytotoxicity Toward Rat Glioma C6 Cells in vitro

“…Modifications in brain excitability (Koroleva and Bures, 1980) and in the redox homeostasis of the brain (El-Bachá et al, 1998;Mendes-da-Silva et al, 2014) are factors that modulate CSD. Analyzing some CSD features (e.g., velocity of propagation) constitutes a very useful way of evaluating brain sensitivity to CSD under conditions that can modify brain excitability (Amaral et al, 2009;Guedes and Abadie-Guedes, 2019) and therefore are clinically relevant. Certain experimental treatments can facilitate CSD propagation, whereas other treatments can antagonize CSD (Guedes and Abadie-Guedes, 2019).…”

“…CSD is a reversible response of the brain tissue to electrical, mechanical, or chemical stimuli. The response consists of cell depolarization with subsequent electrical depression, which propagates slowly over the tissue ( Leão, 1944 , 1947 ; Guedes and Abadie-Guedes, 2019 ). CSD has been further electrophysiologically described in many animal species ( Gorji, 2001 ) and in humans ( Dreier et al, 2019 ).…”

“…Analyzing some CSD features (e.g., velocity of propagation) constitutes a very useful way of evaluating brain sensitivity to CSD under conditions that can modify brain excitability ( Amaral et al, 2009 ; Guedes and Abadie-Guedes, 2019 ) and therefore are clinically relevant. Certain experimental treatments can facilitate CSD propagation, whereas other treatments can antagonize CSD ( Guedes and Abadie-Guedes, 2019 ). These treatments can help in the comprehension of the CSD mechanisms and perhaps shed light on the mechanisms of CSD-related diseases, such as epilepsy ( Leão, 1944 , 1972 ; Guedes and Cavalheiro, 1997 ; Guedes and Abadie-Guedes, 2019 ).…”

“…Certain experimental treatments can facilitate CSD propagation, whereas other treatments can antagonize CSD ( Guedes and Abadie-Guedes, 2019 ). These treatments can help in the comprehension of the CSD mechanisms and perhaps shed light on the mechanisms of CSD-related diseases, such as epilepsy ( Leão, 1944 , 1972 ; Guedes and Cavalheiro, 1997 ; Guedes and Abadie-Guedes, 2019 ).…”