{"doi":"10.1016/j.niox.2024.11.001","title":"Downregulation of neuronal nitric oxide synthase (nNOS) within the paraventricular nucleus in Ins2Akita-type-1 diabetic mice contributes to sympatho-excitation","abstract":"Activation of both renin-angiotensin system (RAS) and the sympathetic system is the primary etiologic event in developing cardiovascular complications in diabetes mellitus (DM). However, the precise mechanisms for sympathetic activation in DM have not been elucidated. Here we attempted to investigate diabetes-linked cardiovascular dysregulation due to angiotensin II (Ang II)-mediated reduction in neuronal nitric oxide (NO) synthase (nNOS) within the paraventricular neuleus (PVN). In the present study, we used Ins2 +/- Akita (a spontaneous, insulin-dependent genetic diabetic non-obese murine model) and wild-type (WT) littermates mice as controls. At 14 weeks of age, we found the Akita mice had increased renal sympathetic nerve activity and elevated levels of plasma norepinephrine. There was decreased expression of nNOS protein (Akita 0.43 ± 0.11 vs. WT 0.75 ± 0.05, P < 0.05) in the PVN of Akita mice. Akita mice had increased expression of angiotensin-converting enzyme (ACE) (Akita 0.58 ± 0.05 vs. WT 0.34 ± 0.04, P < 0.05) and Ang II type 1 receptor (Akita 0.49 ± 0.03 vs. WT 0.29 ± 0.09, P < 0.05), decreased expressions of ACE2 (Akita 0.17 ± 0.05 vs. WT 0.27 ± 0.03, P < 0.05) and angiotensin (1-7) Mas receptor (Akita 0.46 ± 0.02 vs. WT 0.77 ± 0.07, P < 0.05). Futher, there were increased protein levels of protein inhibitor of nNOS (PIN) (Akita 1.75 ± 0.08 vs. WT 0.71 ± 0.09, P < 0.05) with concomitantly decreased catalytically active dimers of nNOS (Akita 0.11 ± 0.04 vs. WT 0.19 ± 0.02, P < 0.05) in the PVN in Akita mice. Our studies suggest that activation of the excitatory arm of RAS, leads to a decrease NO, causing an over-activation of the sympathetic drive in DM. • The details of Akita mice model have been represented in the Discussion (Page 10) as requested. • •We have converted the data from Table 1 to a graph form ( Figure 1 ) as requested. • •We have updated the text in the introduction and the discussion with current reference list. • Our previous work shows the causative link between nNOS in the PVN and regulation of sympathetic nerve activity. Here we attempted to demonstrate a similar relationship between nNOS regulation in the PVN specifically its active form and interaction with Ang II in Akita mice. We have now modified the text to acknowledge the inference of these data based on our previous work as requested. • We appreciate the suggestion that this work would be further confirmed/evaluated by some intervention such as pharmacological, siRNA etc. Here we attempted to demonstrate the basic relationship between nNOS regulation in the PVN and SNA in Akita mice with the background of causality from our previous observations. • The novelty is the observation of changes in nNOS in the PVN of Akita mice with concomitant changes in sympathetic nerve activity consistent with a role for the excitatory arm of the RAS affecting nNOS leading to increase in sympathetic nerve activity in Akita mice. Most of our previous work is a heart failure model in rats. • References are updated. • Statistical analysis section states are corrected now (Page 8). • RSNA measure e.g. Int RSNA is stated in the figure legend ( Figure 2 ). • The KCl induced maximal RSNA was not different between the two groups. This is now stated in the text (Page 9). • The text is now modified to provide some discussion/explanation for the changes in masR (Page 11). • Due to the tiny protein quantity of the mice PVN, when we did the Western blot, we cut the membrane into strips according to the molecular weight of the standard. This allowed us to test 2-3 different molecular weight proteins in a single blot. At this point, we won’t be able to provide the full Western blots gel image as requested.","journal":"Nitric Oxide","year":2024,"id":472365,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":2,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9575,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":284729,"name":"Lie Gao","orcid":"0000-0002-7880-7213","position":1,"is_corresponding":false},{"id":1307807,"name":"Shane Boomer","orcid":null,"position":2,"is_corresponding":false},{"id":368979,"name":"Xuefei Liu","orcid":"0000-0002-1843-6107","position":3,"is_corresponding":false},{"id":367138,"name":"Kaushik P. Patel","orcid":"0000-0002-4500-0819","position":4,"is_corresponding":false},{"id":493909,"name":"Hong Zheng","orcid":"0000-0002-1660-3573","position":5,"is_corresponding":false},{"id":678517,"name":"Tapan Patel","orcid":"0000-0002-0631-5412","position":0,"is_corresponding":true}],"reference_count":57,"raw_metadata":null,"created_at":"2026-07-19T02:05:53.032464Z","pmid":"39521242","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}