Biology subjects

Novaes, L. S.

Publications and source records attributed to Novaes, L. S..

3 recordsLinked to original sources

bioRxiv2026

Isl1+ Central Amygdala Neurons Coordinate Control of the Jaw and Stomach During Ingestion

Central Amygdala neurons expressing Isl1 (CeAIsl1+) project to brainstem regions involved in control of the jaw and the stomach, including the parabrachial nucleus (PBN), the nucleus of the tractus solitary (NTS), and the parvocellular reticular nucleus (PCRt). Stimulation of CeAIsl1+ cells elicits fictive feeding, particularly biting. Activation of these neurons can rate dependently set the amplitude of bite force and inhibition dramatically reduces bite force. Findings suggest this force generation depends on modulation of a jaw closing reflex involving tooth sensory neurons in the mesencephalic trigeminal nucleus (Me5). Anatomical tracing studies show Me5 neurons receive synaptic input from CeAIsl1+ neurons. Patch clamp recordings of Me5 neurons indicate this synapse is mediated by GABA yet depolarizing. Activation of CeAIsl1+ neurons is capable of dramatically potentiating the periodontal jaw closing reflex, a reflex whereby Me5 tooth sensory neurons activate jaw closing muscles. In addition to controlling the actions of the jaw, CeAIsl1+ neuron stimulation is sufficient to reduce gastric pH. Inhibition experiments show these cells are necessary for lowering gastric pH in mice anticipating a meal. Finally, CeAIsl1+ neurons can modulate gastric motility, stimulation transiently suppresses gastric motility, an effect also observed when animals chewed food. Subdiaphragmatic vagotomy eliminated the transient suppression of gastric motility otherwise observed with CeAIsl1+ neuron stimulation or food chewing. Taken together, this molecularly and anatomically defined population generates specific motor patterns of ingestion that involve not only release of oromotor patterns, but also modulation of gastric functions.

physiology↗

bioRxiv2022

Genomic effects of the glucocorticoid receptor guide the acute stress-induced delayed anxiety and basolateral amygdala spine plasticity in rats

Anxiety, a state related to anticipatory fear, can be adaptive in the face of environmental threats or stressors. However, anxiety can also become persistent and manifest as anxiety-and stress-related disorders, such as generalized anxiety or post-traumatic stress disorder (PTSD). In rodents, systemic administration of glucocorticoids (GCs) or short-term restraint stress induces anxiety-like behaviors and dendritic branching within the basolateral complex of the amygdala (BLA) ten days later. Additionally, increased arousal-related memory retention mediated by elevated GCs requires concomitant noradrenaline (NE) signaling, both acting in the BLA. It is unknown whether GCs and NE play a role in the delayed acute stress-induced effects on behavior and BLA dendritic plasticity. Here, inhibiting corticosterone (CORT) elevation during two hours of restraint stress prevents stress-induced increases in delayed anxiety-like behavior and BLA dendritic spine density in rats. Also, we show that the delayed acute stress-induced effects on behavior and morphological alterations are critically dependent on genomic glucocorticoid receptor (GR) actions in the BLA. Unlike CORT, the pharmacological enhancement of NE signaling in the BLA was insufficient to drive delayed anxiety-related behavior. Nonetheless, the delayed anxiety-like behavior ten days after acute stress requires NE signaling in the BLA during stress exposure. Therefore, we define the essential roles of two stress-related hormones for the late stress consequences, acting at two separate times: CORT, via GR, immediately during stress and NE, via beta-adrenoceptors, during the expression of delayed anxiety. Significance StatementThe dysregulation in orchestrating and finetuning major stress-related neural circuitries leads to enhanced reactivity and other altered ways of coping with threatening situations, predisposing humans to multiple psychiatric disorders, including anxiety and PTSD. Given the tremendous burden of affective disorders, we must advance our understanding of stress neurobiology and translate this into improved treatments. Here we showed that the absence of neuronal genomic GR signaling in the BLA prevented delayed effects on anxiety-like behavior and dendritic spine density ten days after stressor exposure. We also demonstrate that CORT, via GR and immediately at stress and NE, via beta-adrenoceptors, during the expression of delayed behavior contribute to the late stress consequences.

neuroscience↗

bioRxiv2021

Norepinephrine and glucocorticoids modulate chronic unpredictable stress-induced increase in the type 2 CRF and glucocorticoid receptors in brain structures related to the HPA axis activation.

The stress response is multifactorial and enrolls circuitries to build a coordinated reaction, leading to behavioral, endocrine, and autonomic changes. These changes are mainly related to the hypothalamus-pituitary-adrenal (HPA) axis activation and the organisms integrity. However, when self-regulation is ineffective, stress becomes harmful and predisposes the organism to pathologies. The chronic unpredictable stress (CUS) is a widely used experimental model since it induces physiological and behavioral changes and better mimics the stressors variability encountered in daily life. Corticotropin-releasing factor (CRF) and glucocorticoid (GCs) are deeply implicated in the CUS-induced physiological and behavioral changes. Nonetheless, the CUS modulation of CRF receptors and GR and the norepinephrine role in extra-hypothalamic brain areas were not well explored. Here, we show that 14-days of CUS induced a long-lasting HPA axis hyperactivity evidenced by plasmatic corticosterone increase and adrenal gland hypertrophy, which was dependent on both GCs and NE release induced by each stress session. CUS also increased CRF2 mRNA expression and GR protein levels in fundamental brain structures related to HPA regulation and behavior, such as the lateral septal nucleus intermedia part (LSI), ventromedial hypothalamic nucleus (VMH), and central nucleus of the amygdala (CeA). We also showed that NE participates in the CUS-induced increase in CRF2 and GR levels in the LSI, reinforcing the locus coeruleus (LC) involvement in the HPA axis modulation. Despite the CUS-induced molecular changes in essential areas related to anxiety-like behavior, this phenotype was not observed in CUS animals 24 h after the last stress session. HighlightsO_LICUS persistently increased plasma CORT levels via GCs and NE signaling. C_LIO_LICUS persistently increased CRF2 mRNA in extra-hypothalamic brain areas. C_LIO_LICUS increased GR protein levels in brain regions related to GCs release control. C_LIO_LINE and GCs participate in the CUS-induced increase in CRF2 and GR levels. C_LIO_LILSI could be the brain nucleus that dictates the fine-tuned response of CUS. C_LIO_LICUS animals did not present anxiety-like behavior. C_LI

neuroscience↗