Biology subjects

Haga, C.

Publications and source records attributed to Haga, C..

3 recordsLinked to original sources

bioRxiv2025

Gestational Chlorpyrifos Exposure Imparts Lasting Alterations to the Rat Somatosensory Cortex

Chlorpyrifos is an organophosphorus pesticide used extensively in agricultural and residential settings for nearly 60 years. Gestational, sub-acute exposure to chlorpyrifos is linked to increased prevalence of neurodevelopmental disorders. Animal studies have modeled these neurobehavioral detriments, however, the functional alterations in the brain induced by this exposure remain largely unknown. To address this, we used a rat model of gestational chlorpyrifos exposure to interrogate the alterations in the developing somatosensory (barrel) cortex. Rat dams were exposed to chlorpyrifos (5 mg/kg) or vehicle on gestational days 18-21 via subcutaneous injection, with no overt acute toxicity. Acetylcholinesterase was modestly inhibited but returned to baseline levels by postnatal day 12. We performed whole-cell patch clamp recordings on postnatal days 12-20 in both male and female progeny of the treated dams. A spike timing dependent plasticity protocol revealed changes to the normal development of use-dependent plasticity, including interference in long-term synaptic depression. Recording inhibitory synaptic activity revealed an increase in the frequency of spontaneous postsynaptic currents and in paired pulse ratios, in conjunction with a significant decrease in miniature postsynaptic currents. These findings suggest a presynaptic mechanism of inhibited GABA release, with potential disinhibition of inhibitory neurons. Evaluation of barrel cortex development displayed disruptions to normal barrel field patterning, with increases in both the septal area and total barrel field. We provide evidence for functional and structural alterations during brain development induced by in utero exposure to the organophosphorus pesticide chlorpyrifos that may account for the well-established behavioral outcomes. SIGNIFICANCE STATEMENTWe demonstrate persistent alterations to synaptic function and plasticity in the somatosensory cortex following a brief, sub-acute exposure to the organophosphorus pesticide chlorpyrifos in a gestational rat model. These occur in conjunction with structural changes to cellular patterning of this brain region. These previously unknown consequences are potential causal mechanisms to the well-established neurodevelopmental detriments associated with early life exposure to chlorpyrifos. Clarifying these mechanisms could aid in ameliorating or preventing their persistent effects.

neuroscience↗

bioRxiv2022

Sex-specific transcriptomic profiling of reward and sensory brain areas in perinatal fentanyl exposed juvenile mice

Use of the synthetic opioid fentanyl increased [~]300% in the last decade, including among women of reproductive ages. Adverse neonatal outcomes and long-term behavioral disruptions are associated with perinatal opioid exposure. Our previous work demonstrated that perinatal fentanyl exposed mice displayed enhanced negative affect and somatosensory circuit and behavioral disruptions during adolescence. However, little is known about molecular adaptations across brain regions that underlie these outcomes. We performed RNA-sequencing across three reward and two sensory brain areas to study transcriptional programs in perinatal fentanyl exposed juvenile mice. Pregnant dams received 10g/ml fentanyl in the drinking water from embryonic day 0 (E0) through gestational periods until weaning at postnatal day 21 (P21). RNA was extracted from nucleus accumbens (NAc), prelimbic cortex (PrL), ventral tegmental area (VTA), somatosensory cortex (S1) and ventrobasal thalamus (VBT) from perinatal fentanyl exposed mice of both sexes at P35. RNA-sequencing was performed, followed by analysis of differentially expressed genes (DEGs) and gene co-expression networks. Transcriptome analysis revealed DEGs and gene modules significantly associated with exposure to perinatal fentanyl in a sex-wise manner. The VTA had the most DEGs, while robust gene enrichment occurred in NAc. Genes enriched in mitochondrial respiration were pronounced in NAc and VTA of perinatal fentanyl exposed males, extracellular matrix (ECM) and neuronal migration enrichment were pronounced in NAc and VTA of perinatal fentanyl exposed males, while genes associated with vesicular cycling and synaptic signaling were markedly altered in NAc of perinatal fentanyl exposed female mice. In sensory areas from perinatal fentanyl exposed females, we found alterations in mitochondrial respiration, synaptic and ciliary organization processes. Our findings demonstrate distinct transcriptomes across reward and sensory brain regions, with some showing discordance between sexes. These transcriptome adaptations may underlie structural, functional, and behavioral changes observed in perinatal fentanyl exposed mice.

neuroscience↗

bioRxiv2020

Perinatal fentanyl exposure leads to long-lasting impairments in somatosensory circuit function and behavior

One consequence of the opioid epidemic are lasting neurodevelopmental sequelae afflicting adolescents exposed to opioids in the womb. A translationally relevant and developmentally accurate preclinical model is needed to understand the behavioral, circuit, network, and molecular abnormalities resulting from this exposure. By employing a novel preclinical model of perinatal fentanyl exposure, our data reveal that fentanyl has several dose-dependent, developmental consequences to somatosensory function and behavior. Newborn male and female mice exhibit signs of withdrawal and sensory-related deficits that extend at least to adolescence. As fentanyl exposure does not affect dams health or maternal behavior, these effects result from the direct actions of perinatal fentanyl on the pups developing brain. At adolescence, exposed mice exhibit reduced adaptation to sensory stimuli, and a corresponding impairment in primary somatosensory (S1) function. In vitro electrophysiology demonstrates a long-lasting reduction in S1 synaptic excitation, evidenced by decreases in release probability, NMDA receptor-mediated postsynaptic currents, and frequency of miniature excitatory postsynaptic currents, as well as increased frequency of miniature inhibitory postsynaptic currents. In contrast, anterior cingulate cortical neurons exhibit an opposite phenotype, with increased synaptic excitation. Consistent with these canghes, electrocorticograms reveal suppressed ketamine-evoked {gamma} oscillations. Morphological analysis of S1 pyramidal neurons indicate reduced dendritic complexity, dendritic length, and soma size. Further, exposed mice exhibited abnormal cortical mRNA expression of key receptors and neuronal growth and development, changes that were consistent with the electrophysiological and morphological changes. These findings demonstrate the lasting sequelae of perinatal fentanyl exposure on sensory processing and function.

neuroscience↗