[Ca 2+ ]i response to ETBR agonist stimulation by a mean of 39%. These data show for the first time that in VSM of the shark, ETBR activation stimulates both IP3R and RyR, and that cADPR is involved in RyR activation.

In vascular smooth muscle (VSM) of

The dogfish shark Squalus acanthias regulates plasma osmolality and extracellular volume by secreting a fluid from its rectal gland which has a higher NaCl and lower urea concentration than plasma. We have previously identified the presence of a calcium-sensing receptor or polyvalent cation sensing receptor (CaSR) on vascular smooth muscle of the rectal gland artery (RGA) and rectal gland tubules (RGT). Activity of the CaSR is influenced by changes in ionic strength. This led us to speculate that the ingestion of invertebrate sea animals increased plasma ionic strength, resulting in inhibition of the receptor, relaxation of RGA, and reversal of inhibition of chloride secretion by the RGT. In contrast, ingestion of fish could diminish ionic strength and have the opposite effect. To study the effect of changes in extracellular ionic strength, shark Ringers solutions were adjusted to three different ionic strengths with NaCl, but the osmolarities were kept constant by varying the concentration of urea. High ionic strength inhibited and low ionic strength enhanced the response to increasing external Ca2+ from 2.5 to 4.7 mM in RGT. The increase in cytosolic Ca2+ ([Ca2+]i) of cells in low, normal, and high ionic strength Ringers solution was 344 +/- 60, 201 +/- 26, and 114 +/- 15 nmol/L, respectively. The [Ca2+]i responses of RGA to external Ca2+ in Ringers of three different ionic strengths were 323 +/- 43, 231 +/- 14, and 56 +/- 11 nmol/L, respectively. Activation of the CaSR by spermine was reduced by more than 50% by high ionic strength in both RGT and RGA. Whether the small changes in shark plasma ionic strength that occur after a shark ingests marine animals with lower and higher ionic strength modulates salt secretion by the rectal gland is not yet known.

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Background: Even with vaccines approved for children over the age of five, and the FDA granting full approval to the Pfizer-BioNTech SARS-CoV-2 (COVID-19) vaccine, studies have shown that only 36-65% of parents plan to have their child receive a COVID-19 vaccine, indicating the need to investigate parental motivations and apprehensions further. The perceptions and intentions of parents/caregivers in the Athens-Clarke County area must be evaluated to assess barriers to vaccine uptake and provide insight into vaccine hesitancy. Methods: The survey, including demographic questions about the caregivers and children, COVID-19 history, and illnesses in the family, and current COVID-19 vaccination status of the family, was given voluntarily to caregivers of middle school students by middle school staff during parent-teacher conferences in October 2021. Multivariable linear regression was used to calculate statistical significance for whether parents were willing to vaccinate their children with the COVID-19 vaccine for each independent variable collected in the survey. Results: Of the 366 caregivers of middle school aged children in Athens-Clarke County, Georgia who reported their intentions for vaccinating their children, 310 (84.7%) reported intentions to vaccinate their child against COVID-19 and 56 (15.3%) reported that they do not intend to vaccinate their child against COVID-19 when the child becomes eligible. Caregivers who expressed belief that the vaccine is effective were found to be significantly associated with intention to vaccinate their child (p=0.009). If the caregiver had already received the vaccine, they were also significantly more likely to vaccinate their child (p=0.004). The caregiver was also significantly more likely to vaccinate their child if their child had a chronic disease (p<0.001). Conclusion: COVID-19 vaccination hesitancy is a public health concern that has arisen since the FDA emergency authorization of vaccines in December of 2020. Multiple studies have sought to elucidate the answer to this question, however detailed demographic studies have not previously been investigated. Concurrently, no study has focused its population to include the southeastern United States. This study promotes the dissemination of knowledge to allow public health experts a better understanding of the current societal opinions and dissents within the southeastern United States during the COVID-19 pandemic.