Which GABA Receptors Are Expressed in the Zebrafish Lateral Line?

The presence of the neurotransmitter GABA in the mammalian inner ear is well established, yet its role in regulating inner ear cell function is less clear. We seek to understand the role of the GABA in the inner ear using the model organism zebrafish. Zebrafish possess a sense that humans do not: they can detect water movement with their lateral line system. Zebrafish sense water movement with cells that project out from the body of the fish into the environment. These so-called hair cells are remarkably similar to the sensory cells of the cochlea and semi-circular canals. Because they are on the outside of the zebrafish, and not behind a bony skull, lateral line hair cells are easily accessible to study. Therefore, we are determining if we can use the lateral line system to understand more about GABA in the inner ear. We have used RNA extraction and RT-PCR to detect the expression of 27 GABA-related genes in zebrafish. We have also identified a novel alternative exon in one isoform. Overall, our results suggest that the genes expressed in the lateral line are orthologs of genes expressed in the mammalian inner ear, and thus zebrafish appear to be an appropriate model organism with which to further study GABA function in the inner ear

Social connectedness as a determinant of mental health: A scoping review.

Public health and epidemiologic research have established that social connectedness promotes overall health. Yet there have been no recent reviews of findings from research examining social connectedness as a determinant of mental health. The goal of this review was to evaluate recent longitudinal research probing the effects of social connectedness on depression and anxiety symptoms and diagnoses in the general population. A scoping review was performed of PubMed and PsychInfo databases from January 2015 to December 2021 following PRISMA-ScR guidelines using a defined search strategy. The search yielded 66 unique studies. In research with other than pregnant women, 83% (19 of 23) studies reported that social support benefited symptoms of depression with the remaining 17% (5 of 23) reporting minimal or no evidence that lower levels of social support predict depression at follow-up. In research with pregnant women, 83% (24 of 29 studies) found that low social support increased postpartum depressive symptoms. Among 8 of 9 studies that focused on loneliness, feeling lonely at baseline was related to adverse outcomes at follow-up including higher risks of major depressive disorder, depressive symptom severity, generalized anxiety disorder, and lower levels of physical activity. In 5 of 8 reports, smaller social network size predicted depressive symptoms or disorder at follow-up. In summary, most recent relevant longitudinal studies have demonstrated that social connectedness protects adults in the general population from depressive symptoms and disorders. The results, which were largely consistent across settings, exposure measures, and populations, support efforts to improve clinical detection of high-risk patients, including adults with low social support and elevated loneliness