ABSTRACT
Although bile acids play a notable role in depression, the pathological significance of the bile acid TGR5 membrane-type receptor in this disorder remains elusive. Using depression models of chronic social defeat stress and chronic restraint stress in male mice, we found that TGR5 in the lateral hypothalamic area (LHA) predominantly decreased in GABAergic neurons, the excitability of which increased in depressive-like mice. Upregulation of TGR5 or inhibition of GABAergic excitability in LHA markedly alleviated depressive-like behavior, whereas down-regulation of TGR5 or enhancement of GABAergic excitability facilitated stress-induced depressive-like behavior. TGR5 also bidirectionally regulated excitability of LHA GABAergic neurons via extracellular regulated protein kinases-dependent Kv4.2 channels. Notably, LHA GABAergic neurons specifically innervated dorsal CA3 (dCA3) CaMKIIα neurons for mediation of depressive-like behavior. LHA GABAergic TGR5 exerted antidepressant-like effects by disinhibiting dCA3 CaMKIIα neurons projecting to the dorsolateral septum (DLS). These findings advance our understanding of TGR5 and the LHAGABAâdCA3CaMKIIαâDLSGABA circuit for the development of potential therapeutic strategies in depression.
Subject(s)
Depression , GABAergic Neurons , Hypothalamic Area, Lateral , Receptors, G-Protein-Coupled , Animals , Male , Mice , Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism , Depression/metabolism , Disease Models, Animal , GABAergic Neurons/metabolism , GABAergic Neurons/physiology , Hypothalamic Area, Lateral/metabolism , Mice, Inbred C57BL , Neural Pathways/metabolism , Receptors, G-Protein-Coupled/metabolism , Receptors, G-Protein-Coupled/genetics , Septal Nuclei/metabolism , Social Defeat , Stress, Psychological/metabolismABSTRACT
China's immunization programme is relatively strong, with latest WHO-UNICEF monitoring rates for 2019 showing national vaccination coverage over 90%. However, vaccination coverage is heterogeneous, varying across geographic regions, rural-urban communities, and sub-populations. We conducted a qualitative study from a critical realist perspective, analyzing semi-structured interviews with 26 vaccination providers in three provinces, selected to represent regional socioeconomic disparities across Eastern, Central, and Western China. We analyzed data thematically, using deductive and inductive coding. Providers reported vaccination coverage in their areas had increased significantly, but remained lower among migrant and left-behind children. Main coverage determinants were child-related (i.e. gender, number, health status), caregiver-related (i.e. socioeconomic status, role, education level, ethnicity), institution-related (i.e. vaccinator numbers, information system, appointment process), and system-related (i.e. vaccine supply, intersectoral cooperation, vaccine 'hesitancy'). Potentially effective measures to promote vaccination coverage included using routine maternal and child health-care visits for catch-up vaccination, providing additional health education, conducting follow-up family visits by village doctors, and requiring vaccination verification at school enrollment. This is the first qualitative study to examine potential determinants of low vaccination coverage in these areas of China. Findings can inform policies to strengthen the role of schools, develop the national immunization information system, and promote appointment apps. More consideration is needed to improve service quality and eliminating inequities, such as strengthening health education and service provision for migrant and left-behind children.
