Magnocellular neuroendocrine cells of the supraoptic nucleus (SON) release vasopressin (VP) systemically and locally during osmotic challenge. Although both central VP and nitric oxide (NO) release appear to reduce osmotically stimulated systemic VP release, it is unknown whether they interact locally in the SON to enhance somatodendritic release of VP, a phenomenon believed to regulate systemic VP release. In this study, we examined the contribution of VP receptor subtypes and NO to local VP release from the rat SON elicited by systemic injection of 3.5 m saline. Treatment of SON punches with VP receptor antagonists decreased osmotically stimulated intranuclear VP release. Similarly, blockade of NO production, or addition of NO scavengers, reduced stimulated VP, glutamate, and aspartate release, suggesting that local NO production and activity are critical for osmotically induced intranuclear VP and excitatory amino acid release. An increase in endogenous NO release from SON punches in response to hyperosmolality was confirmed by enzymatic NO assay. Consistent with enhanced glutamate and VP release from stimulated rat SON punches, the ionotropic glutamate receptor blocker kynurenate decreased stimulated local VP release without affecting NO release. These data suggest that NO enhances local VP release in part by facilitating local release of glutamate/aspartate and that glutamate receptor activity is required for the stimulation of local VP release by osmotic challenge. Collectively, these results suggest that local VP receptors, NO, and glutamatergic signaling mediate the amplification of intranuclear VP release during hyperosmolality and may contribute to efficient, but not exhaustive, systemic release of VP during osmoregulatory challenge.

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Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are environmental pollutants that produce neurotoxicity and neuroendocrine disruption. They affect the vasopressinergic system but their disruptive mechanisms are not well understood. Our group reported that rats perinatally exposed to Aroclor-1254 (A1254) and DE-71 (commercial mixtures of PCBs and PBDEs) decrease somatodendritic vasopressin (AVP) release while increasing plasma AVP responses to osmotic activation, potentially emptying AVP reserves required for body-water balance. The aim of this research was to evaluate the effects of perinatal exposure to A1254 or DE-71 (30mgkg/day) on AVP transcription and protein content in the paraventricular and supraoptic hypothalamic nuclei, of male and female rats, by in situ hybridization and immunohistochemistry. cFOS mRNA expression was evaluated in order to determine neuroendocrine cells activation due to osmotic stimulation. Animal groups were: vehicle (control); exposed to either A1254 or DE-71; both, control and exposed, subjected to osmotic challenge. The results confirmed a physiological increase in AVP-immunoreactivity (AVP-IR) and gene expression in response to osmotic challenge as reported elsewhere. In contrast, the exposed groups did not show this response to osmotic activation, they showed significant reduction in AVP-IR neurons, and AVP mRNA expression as compared to the hyperosmotic controls. cFOS mRNA expression increased in A1254 dehydrated groups, suggesting that the AVP-IR decrease was not due to a lack of the response to the osmotic activation. Therefore, A1254 may interfere with the activation of AVP mRNA transcript levels and protein, causing a central dysfunction of vasopressinergic system.

Purpose: Airway manipulation is a high-risk procedure due to aerosolization of viral particles. This has become of paramount importance during the COVID-19 pandemic in an effort to protect personnel involved in airway management. We designed and tested a copper frame to support a plastic drape to contain aerosols and allow for reduction of risk during airway management. The “CopperHead” frame allows airway management with minimal limitations in a wide range of scenarios including elective and urgent intubations, management of unstable patients, cardiopulmonary resuscitation (CPR), bronchoscopy, and extubation. The frame was made of copper to utilize its inherent antimicrobial and antiviral properties. Intervention and Measurements: We performed multiple simulations to measure FiO2 accumulation underneath the frame and plastic drape. We also performed defibrillations on a mannequin with the apparatus in place to evaluate for safety during times that the device is not removed prior to defibrillation, as indicated. We then deployed the device throughout our hospital and analyzed the resulting data on procedure success and infection rates in both COVID-positive and COVID-negative cohorts.Main Results: The technique is reproducible and allows for airway manipulation in COVID-19 suspected or confirmed patients. The FiO2 under the copper frame and plastic drape increased, but quickly dispersed when the frame was removed. We performed multiple defibrillations with apparatus in place with no adverse events. We showed that with the device in place, there appears to be no hindrance to successful intubation with 94 successful procedures in 74 patients and an 87% (60/69) first-pass intubation rate, and there were no documented clinicians or respiratory therapy infections through exposures to COVID-19 positive patients.Conclusions: The addition of a copper frame to a plastic drape over patients was an effective way to improve the safety and ease of intubation in the COVID-19 pandemic. This device was well received among our clinicians and served to benefit both intubation and extubation of recovered patients.

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