Horii-Hayashi, N. | Search bioRxiv

bioRxiv2024

Element accumulation in the tracheal and bronchial cartilages of monkeys

Compositional changes in the tracheal and bronchial cartilages can affect respiratory ventilation and lung function. We aimed to elucidate element accumulation in the tracheal and bronchial cartilages of monkeys and divided it into four sites: tracheal, tracheal bifurcation, left bronchial, and right bronchial cartilages. The elemental content was analyzed using inductively coupled plasma atomic emission spectrometry. The average calcium content was two to three times higher in the tracheal cartilage than in the other three cartilages. The trends of phosphorus and zinc were similar to those of calcium. The average calcium, phosphorus, and zinc contents were the highest in the tracheal cartilage and decreased in the following order: the left bronchial, right bronchial, and tracheal bifurcation cartilages. These findings revealed that differences existed in element accumulation between different sites within the same airway cartilage and that calcium, phosphorus, and zinc accumulation mainly occurred in the tracheal cartilage. A substantial direct correlation was observed between age and calcium content in the tracheal and bronchial cartilages and all such monkeys with high calcium content were > four years of age. These results suggest that calcium accumulation occurs in the tracheal and bronchial cartilages after reaching a certain age. An extremely substantial direct correlation was observed between calcium and phosphorus contents in the tracheal and bronchial cartilages. This finding is similar to the previously published calcium and phosphorus correlations in several other cartilages, suggesting that the calcium and phosphorus contents of cartilage exist in a certain ratio.

zoology↗

bioRxiv2022

A Checking Model of Obsessive-Compulsive Disorder Based on the Hypothalamic Defensive System Against a Potential Threat

BACKGROUNDObsessive-compulsive disorder (OCD) is a psychiatric disorder characterized by obsessive thoughts and compulsive behavior. While some theories imply that OCD patients have cognitive biases and dysfunctional motivation regarding a potential threat, these views are not adequately supported by neurological evidence. Hypothalamic perifornical (PeF) urocortin-3 (UCN3) neurons are involved in defensive responses to a potential threat, and the activation of these neurons in mice induces repetitive and excessive checking and burying of novel objects. In this study, we evaluated the hypothesis that mice in which PeF UCN3 neurons are activated can serve as an OCD model. METHODSPeF UCN3 neurons were chemogenetically activated with clozapine-N oxide (CNO) in Ucn3-Cre mice. Marble-burying activity, repetitive/stereotypic behaviors in the homecage, and excessive responses to a novel object were measured as OCD-like behaviors. The effects of clinically used drugs for treating OCD on these behaviors were evaluated. The effect of CNO on neural activity in the cortico-striato-thalamo-cortical loop (which is regarded as an OCD circuit) was assessed with c-Fos immunolabeling. RESULTSCNO increased marble-burying activity, evoked homecage-specific repetitive/stereotypic behaviors that probably aimed to seal entrances, and induced repetitive and excessive checking and burying of novel objects. These behaviors were suppressed by selective serotonin-reuptake inhibitors but not by diazepam. CNO increased neural activity in the cortico-striato-thalamo-cortical loop. CONCLUSIONSThese results indicated that mice whose PeF UCN3 neurons are activated can serve as a model of OCD, particularly as a checking model. This supports theories concerning the role of potential threats in the pathophysiology of OCD.

animal behavior and cognition↗