查看更多>>摘要:The stress response is essential for animal self-defense and survival.However,species may exhibit stress response variation depending on their specific environmental and selection pressures.Blind cavefish dwell in cave environments,which differ markedly in stressors and resource availability compared to surface aquatic environments.However,whether blind cavefish exhibit differences in stress response as an adaptation to their cave environments remains unclear.Here,we investigated differences in stress response in six closely related Triplophysa species,including three blind cavefish(T.longibarbata,T.jiarongensis,and T.rosa)and three normal-sighted river fish(T.nasobarbatula,T.dongsaiensis,and T.bleekeri).Results showed that blind cavefish exhibited a range of distinct behavioral responses compared to sighted river fish,including greater levels of activity,shorter duration of freezing,absence of erratic movements or thrashing behavior,and opposite behavioral trends over time.Furthermore,the cavefish species demonstrated attenuated increases in metabolic rate in response to stressors related to novel environments.Cave-dwelling T.rosa also exhibited lower basal hypothalamic-pituitary-inter-renal(HPI)axis-related gene expression levels and stress hormone concentrations compared to river-dwelling T.bleekeri.These results suggest that blind cavefish may have lost their behavioral stress response,potentially mediated by a reduction in basal activity of the HPI axis,thus enabling the conservation of energy by reducing unnecessary expenditure in energy-limited caves.
查看更多>>摘要:The sizes of Astyanax mexicanus blind cavefish populations of North-East Mexico are demographic parameters of great importance for investigating a variety of ecological,evolutionary,and conservation issues.However,few estimates have been obtained.For these mobile animals living in an environment difficult to explore as a whole,methods based on capture-mark-recapture are appropriate,but their feasibility and interpretation of results depend on several assumptions that must be carefully examined.Here,we provide evidence that minimally invasive genetic identification from captures at different time intervals(three days and three years)can give insights into cavefish population size dynamics as well as other important demographic parameters of interest.We also provide tools to calibrate sampling and genotyping efforts necessary to reach a given level of precision.Our results suggest that the El Pachón cave population is currently very small,of an order of magnitude of a few hundreds of individuals,and is distributed in a relatively isolated area.The probable decline in population size in the El Pachón cave since the last census in 1971 raises serious conservation issues.
查看更多>>摘要:Delirium is a severe acute neuropsychiatric syndrome that commonly occurs in the elderly and is considered an independent risk factor for later dementia.However,given its inherent complexity,few animal models of delirium have been established and the mechanism underlying the onset of delirium remains elusive.Here,we conducted a comparison of three mouse models of delirium induced by clinically relevant risk factors,including anesthesia with surgery(AS),systemic inflammation,and neurotransmission modulation.We found that both bacterial lipopolysaccharide(LPS)and cholinergic receptor antagonist scopolamine(Scop)induction reduced neuronal activities in the delirium-related brain network,with the latter presenting a similar pattern of reduction as found in delirium patients.Consistently,Scop injection resulted in reversible cognitive impairment with hyperactive behavior.No loss of cholinergic neurons was found with treatment,but hippocampal synaptic functions were affected.These findings provide further clues regarding the mechanism underlying delirium onset and demonstrate the successful application of the Scop injection model in mimicking delirium-like phenotypes in mice.