Biology subjects

Bravo, L.

Publications and source records attributed to Bravo, L..

2 recordsLinked to original sources

bioRxiv2024

Sex differences in the impact of nerve injury on Locus Coeruleus function and behaviour in mice

Chronic pain often coexists with stress-related disorders such as anxiety and depression, with a higher prevalence in women. Rodent studies reveal significant sex differences in pain and stress-related behaviours, emphasising the need to explore underlying neurobiological mechanisms. The locus coeruleus (LC), the main noradrenergic nucleus in the brainstem, plays a crucial role in modulating pain and stress responses and exhibits sex-specific characteristics. In this study, we investigated the effects of neuropathic pain on the LC in male and female mice, focusing on sensory thresholds, emotional states, and cognitive function. Nerve injury caused immediate sensory hypersensitivity in both sexes, while depressive-like behaviours and cognitive impairments emerged only after prolonged injury. Interestingly, anxiety-like behaviours and heightened fear conditioning were exclusive to males, which correlated with specific structural and functional changes in the male LC, such as increased noradrenergic cell counts, larger somato-dendritic volume, and greater neuron excitability. In females, however, neuronal excitability was reduced. Chemogenetic inhibition of LC neurons alleviated depressive- and anxiety-like behaviours, as well as fear conditioning, but only in males. Overall, neuropathic pain induces distinct behavioural and neurobiological responses in males and females, challenging traditional views on female vulnerability to pain-induced anxiety and highlighting the need for sex-specific LC-targeted therapies.

neuroscience↗

bioRxiv2020

Durable Changes to Airway Mucus and Fluid Secretion Following Cholinergic Challenge

PurposeMucus abnormalities are central to the pathophysiology of several chronic airway diseases. Mucus secretion and clearance are regulated, in part, by cholinergic innervation. Prolonged cholinergic stimulation may contribute to mucus abnormalities in disease. Thus, we tested the hypothesis that prolonged cholinergic stimulation gives rise to lasting mucus abnormalities in airways. MethodsWe delivered aerosolized bethanechol, a cholinergic agonist, to pig airways. Forty-eight hours later, we measured mucus secretion and mucociliary transport in tracheal segments ex vivo. Tracheal and bronchoalveolar lavage concentrations of the major secreted mucus glycoproteins, mucin5B (MUC5B) or mucin5AC (MUC5AC), were measured with ELISA and antibody labeling. Pig airway epithelia were cultured at the air-liquid interface and treated with bethanechol for forty-eight hours. Stimulated fluid secretion was measured with reflected microscopy and Ussing chambers were used to measure ion transport. ResultsAirways from bethanechol-challenged pigs exhibited sheet-like mucus films, which were not associated with a greater abundance of MUC5AC or MUC5B. Epithelia treated with bethanechol had diminished fluid secretion and decreased Cl- transport. However, mucus and fluid alterations were not associated with impaired mucociliary transport. ConclusionsThese data suggest that cholinergic transmission induces sustained alterations in airway mucus properties. Such defects might compound and/or contribute to persistent mucus phenotypes found after the resolution of airway inflammation.

physiology↗