RESUMO
Patients with Alzheimer's disease (AD) often have fragmentation of sleep/wake cycles and disrupted 24-h (circadian) activity. Despite this, little work has investigated the potential underlying day/night disruptions in cognition and neuronal physiology in the hippocampus. The molecular clock, an intrinsic transcription-translation feedback loop that regulates circadian behavior, may also regulate hippocampal neurophysiological activity. We hypothesized that disrupted diurnal variation in clock gene expression in the hippocampus corresponds with loss of normal day/night differences in membrane excitability, synaptic physiology, and cognition. We previously reported disrupted circadian locomotor rhythms and neurophysiological output of the suprachiasmatic nucleus (the primary circadian clock) in Tg-SwDI mice with human amyloid-beta precursor protein mutations. Here, we report that Tg-SwDI mice failed to show day/night differences in a spatial working memory task, unlike wild-type controls that exhibited enhanced spatial working memory at night. Moreover, Tg-SwDI mice had lower levels of Per2, one of the core components of the molecular clock, at both mRNA and protein levels when compared to age-matched controls. Interestingly, we discovered neurophysiological impairments in area CA1 of the Tg-SwDI hippocampus. In controls, spontaneous inhibitory post-synaptic currents (sIPSCs) in pyramidal cells showed greater amplitude and lower inter-event interval during the day than the night. However, the normal day/night differences in sIPSCs were absent (amplitude) or reversed (inter-event interval) in pyramidal cells from Tg-SwDI mice. In control mice, current injection into CA1 pyramidal cells produced more firing during the night than during the day, but no day/night difference in excitability was observed in Tg-SwDI mice. The normal day/night difference in excitability in controls was blocked by GABA receptor inhibition. Together, these results demonstrate that the normal diurnal regulation of inhibitory transmission in the hippocampus is diminished in a mouse model of AD, leading to decreased daytime inhibition onto hippocampal CA1 pyramidal cells. Uncovering disrupted day/night differences in circadian gene regulation, hippocampal physiology, and memory in AD mouse models may provide insight into possible chronotherapeutic strategies to ameliorate Alzheimer's disease symptoms or delay pathological onset.
Assuntos
Precursor de Proteína beta-Amiloide/genética , Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/genética , Ritmo Circadiano/genética , Regulação da Expressão Gênica/genética , Hipocampo/metabolismo , Hipocampo/fisiopatologia , Memória Espacial , Transmissão Sináptica , Animais , Região CA1 Hipocampal/metabolismo , Região CA1 Hipocampal/fisiopatologia , Potenciais Pós-Sinápticos Excitadores/genética , Feminino , Antagonistas GABAérgicos/farmacologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Células Piramidais , Receptor PAR-2/biossíntese , Receptor PAR-2/genéticaRESUMO
In recent history, the world has witnessed a trend towards liberalization of abortion laws driven by an increasing understanding of the negative personal and public health consequences of criminalizing abortion. By contrast, several countries have recently implemented restrictive reproductive laws, joining the 112 countries where access to abortion care is banned completely or with narrow exceptions. On June 24, 2022, the US Supreme Court ruling in Dobbs v Jackson Women's Health Organization overturned its landmark decisions in Roe v Wade that established abortion until the point of viability of the fetus as a constitutional right. After Roe v Wade having been overturned, it is projected that many women in the USA will be prevented from accessing safe abortion care. Importantly, abortion bans not only impose constraints on patient autonomy, they also restrict physicians' ability to practice evidence-based medicine, which will negatively impact psychiatric care. It is therefore crucial for the practicing psychiatrist to be familiar with this new legal landscape. In this Personal View, we aim to provide a topical overview to help clinicians gain a clear understanding of legal, clinical, and ethical responsibilities, focusing on the USA. We also discuss the reality that psychiatrists might be called upon to determine medical necessity for an abortion on psychiatric grounds, which is new for most US psychiatrists. We predict that psychiatrists will be confronted with very difficult situations in which lawful and ethical conduct might be incongruent, and that abortion bans will result in greater numbers of patients needing psychiatric care from a system that is ill-prepared for additional demands.
RESUMO
Importance: To make progress toward precision psychiatry, it is crucial to move beyond case-control studies and instead capture individual variations and interpret them in the context of a normal range of biological systems. Objective: To evaluate whether baseline deviations from a normative reference range in subcortical volumes are better predictors of antipsychotic treatment response than raw volumes in patients with first-episode psychosis (FEP) who were naive to antipsychotic medication. Design, Setting, and Participants: In this prospective longitudinal study, patients with first-episode psychosis who were referred from different clinical settings (emergency department, inpatient units, and outpatient clinics) at the University of Alabama at Birmingham were included. A total of 286 patients were screened, 114 consented, 104 enrolled in the treatment trial, and 85 completed the trial. Patients were observed for 16 weeks. Controls were matched by age and sex. Data were collected between June 2016 and July 2021, and data were analyzed from August 2021 to June 2022. Interventions: Risperidone on a flexible dosing scheme for 16 weeks. There was an option to switch to aripiprazole for excessive adverse effects. Main Outcomes and Measures: The main outcome of this study was to evaluate, in patients with FEP who were naive to antipsychotic medication, the association of baseline raw volumes and volume deviations in subcortical brain regions with response to antipsychotic medication. Raw brain volumes or volume deviation changes after treatment were not examined. Results: Of 190 included participants, 111 (58.4%) were male, and the mean (SD) age was 23.7 (5.5) years. Volumes and deviations were quantified in 98 patients with FEP, and data from 92 controls were used as comparison for case-control contrasts and reference curve calibration. In case-control contrasts, patients with FEP had lower raw thalamus (P = .002; F = 9.63; df = 1), hippocampus (P = .009; F = 17.23; df = 1), amygdala (P = .01; F = 6.55; df = 1), ventral diencephalon (P = .03; F = 4.84; df = 1), and brainstem volumes (P = .004; F = 8.39; df = 1). Of 98 patients, 36 patients with FEP (36%) displayed extreme deviations. Associations with treatment response significantly differed between raw volume and deviation measures in the caudate (z = -2.17; P = .03) and putamen (z = -2.15; P = .03). Conclusions and Relevance: These data suggest that normative modeling allows capture of interindividual heterogeneity of regional brain volumes in patients with FEP and characterize structural pathology in a clinically relevant fashion. This holds promise for progress in precision medicine in psychiatry, where group-level studies have failed to derive reliable maps of structural pathology.
Assuntos
Antipsicóticos , Transtornos Psicóticos , Adulto , Feminino , Humanos , Masculino , Adulto Jovem , Antipsicóticos/farmacologia , Antipsicóticos/uso terapêutico , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Estudos de Casos e Controles , Estudos Longitudinais , Imageamento por Ressonância Magnética , Estudos Prospectivos , Transtornos Psicóticos/tratamento farmacológico , Transtornos Psicóticos/patologiaRESUMO
Circadian rhythms are biological processes that cycle across 24 h and regulate many facets of neurophysiology, including learning and memory. Circadian variation in spatial memory task performance is well documented; however, the effect of sex across circadian time (CT) remains unclear. Additionally, little is known regarding the impact of time-of-day on hippocampal neuronal physiology. Here, we investigated the influence of both sex and time-of-day on hippocampal neurophysiology and memory in mice. Performance on the object location memory (OLM) task depended on both circadian time and sex, with memory enhanced at night in males but during the day in females. Long-term synaptic potentiation (LTP) magnitude at CA3-CA1 synapses was greater at night compared with day in both sexes. Next, we measured spontaneous synaptic excitation and inhibition onto CA1 pyramidal neurons. Frequency and amplitude of inhibition was greater during the day compared with night, regardless of sex. Frequency and amplitude of excitation was larger in females, compared with males, independent of time-of-day, although both time-of-day and sex influenced presynaptic release probability. At night, CA1 pyramidal neurons showed enhanced excitability (action potential firing and/or baseline potential) that was dependent on synaptic excitation and inhibition, regardless of sex. This study emphasizes the importance of sex and time-of-day in hippocampal physiology, especially given that many neurologic disorders impacting the hippocampus are linked to circadian disruption and present differently in men and women. Knowledge about how sex and circadian rhythms affect hippocampal physiology can improve the translational relevancy of therapeutics and inform the appropriate timing of existing treatments.