Education 

Post Doctoral Fellowship in Neurosciences - Tulane University

Post Doctoral Fellowship in Physiology - Ribeirão Preto School of Medicine - São Paulo State University

MS And PhD In Physiological Sciences - Federal Rural University of Rio de Janeiro

Teaching Degree in Physical Education - Federal Rural University of Rio de Janeiro

Research 

The overall goal of our laboratory is to understand the mechanisms through which the brain controls behavior. We are particularly interested in unraveling how challenges to physiology affect the neural circuits responsible for the stress response and for the control of motivated behaviors, such as feeding and drinking.

Are different neural circuits recruited by different modalities of stress and how do these circuits contribute to distinct behavioral stress responses?

Stress may be broadly defined as any stimulus that is capable of inducing a change in physiology, increasing the activity of the HPA axis and, consequently, the plasma levels of stress hormones, such as corticosterone in rodents or cortisol in humans. This term, however, is largely unspecific, several very distinct stimuli fit the bill to be considered a stressful stimulus. For instance, being exposed to a predator, being hungry and feeling sick are all stressful, however the neural circuits involved with the central processing of fear, hunger and sickness are very distinct, although they all converge on an action on the HPA axis. In this line of research, we aim to understand the different afferent projections to the stress-controlling neurons in the hypothalamus, and how these circuits are engaged by distinct stress modalities.

Which neural network is responsible for the expression of sickness behavior?

In response to inflammation or injury, we assume a more withdrawn motivational state, which can be characterized by lethargy, cachexia and allodynia, among other effects. This behavioral state is denominated sickness behavior, and is present in several species, such as flies, fish, birds, rodents, and humans. Our previous research has demonstrated that specific activation of norepinephrine neurons in the NTS triggers sickness behaviors in mice, in the absence of sources of sickness such as inflammation or infection. This indicates that this specific neurotransmitter system from the hindbrain is involved with the expression of sickness. Now, we aim to test if we can block sickness behaviors by blocking the activity of these neurons, and to assess the possible targets from the efferent neurons in this region.

Publications

FLORES, R.A.; DOS-SANTOS, RAONI C.; RODRIGUES-SANTOS, I.; JESUS, A.A.; ANTUNES-RODRIGUES, J.; ELIAS, L.L. Tonic noradrenergic input to neurons in the dorsal raphe nucleus mediates food intake in male mice. Behavioral Brain Research, 2024. DOI: 10.1016/j.bbr.2024.114872

DOS-SANTOS, RAONI C.; SWEETEN, B.L.W.; STELLY, C.E.; TASKER, J.G. The Neuroendocrine Impact of Acute Stress on Synaptic Plasticity. Endocrinology, 2023. doi: 10.1210/endocr/bqad149

DOS-SANTOS, RAONI C.; ISHIOKA, G.; COGNUCK, S.Q.; MANTOVANI, M.; CALIMAN, I.F.; ELIAS, L.L.K.; ANTUNES-RODRIGUES, J. High-fat diet changes the behavioural and hormonal responses to water deprivation in male Wistar rats. Experimental Physiology, 2022. DOI: 10.1113/EP090513

DOS-SANTOS, RAONI C.; REIS, L.C.; PERELLO, M.; FERGUSON, A.V.; MECAWI, A. S. The actions of ghrelin in the paraventricular nucleus: energy balance and neuroendocrine implications. Annals of the New York Academy of Sciences, 2019. DOI: 10.1111/nyas.14087

DOS-SANTOS, RAONI C.; GROVER, H.M.; REIS, L.C.; FERGUSON, A.V.; MECAWI, A.S. Electrophysiological Effects of Ghrelin in the Hypothalamic Paraventricular Nucleus Neurons. Frontiers in Cellular Neuroscience, 2018. DOI: 10.3389/fncel.2018.00275

Find Dr. Dos Santos on PubMed.