{"id":"77b517b2-c4b3-5848-b16b-188949540710","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:c-scurvy-vascular-responsiveness","predicate":"deficiency_reduces_forearm_adrenergic_response","statement":"Forearm vasoconstriction to intra-arterial norepinephrine and tyramine was greater after repletion; four subjects also had lower resistance-vessel responsiveness to lower-body negative pressure during deficiency.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"a8e5b7c5-a458-55b4-8544-7282a749ec48","mechanism_event_label":"The blood vessels responded less strongly to some constricting signals during shortage.","subject":{"id":"da1a7137-08f2-5a36-8bb6-377fbd32e327","slug":"vitamin-c","display_name":"Vitamin C","entity_type_key":"chemical_species"},"object":{"id":"b4faf685-56db-5d71-aa95-48419b86bc29","slug":"forearm-adrenergic-vasoconstriction","display_name":"Forearm vasoconstriction to adrenergic stimuli","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"a8e5b7c5-a458-55b4-8544-7282a749ec48","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:c-scurvy-vascular-responsiveness-event","event_type":"observed_intervention","label":"The blood vessels responded less strongly to some constricting signals during shortage.","description":"Forearm vasoconstriction to intra-arterial norepinephrine and tyramine was greater after repletion; four subjects also had lower resistance-vessel responsiveness to lower-body negative pressure during deficiency.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"34ab29ee-eb2b-5e51-9d25-0c1f8d5b97d9","slug":"norepinephrine","display_name":"Norepinephrine","entity_type_key":"small_molecule"},"role":"experimental_agonist","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"da1a7137-08f2-5a36-8bb6-377fbd32e327","slug":"vitamin-c","display_name":"Vitamin C","entity_type_key":"chemical_species"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"b4faf685-56db-5d71-aa95-48419b86bc29","slug":"forearm-adrenergic-vasoconstriction","display_name":"Forearm vasoconstriction to adrenergic stimuli","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"nutrient_deficiency","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"experimental_model","value_text":"Five volunteers studied after three months of vitamin C deprivation and again after four months of repletion.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Clinical scurvy; forearm blood flow, pressure, catecholamines and responses to lower-body negative pressure, norepinephrine and tyramine.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Does not isolate endothelial, smooth-muscle or collagen mechanisms.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin C research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-c","display_name":"Vitamin C","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"The blood vessels responded less strongly to some constricting signals during shortage.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[c-abboud1970] Autonomic reflexes and vascular reactivity in experimental scurvy in man (1970). https://pubmed.ncbi.nlm.nih.gov/5411783/ DOI: 10.1172/jci106239","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Human blood or whole-person endpoints","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"nutrient_deficiency","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"6bdfc955-3000-5403-98b5-859bff76f02a","evidence_kind":"source_excerpt","locator":"Lines 1529-1539","start_line":1529,"end_line":1539,"excerpt":"### c-scurvy-vascular-responsiveness\nForearm vasoconstriction to intra-arterial norepinephrine and tyramine was greater after repletion; four subjects also had lower resistance-vessel responsiveness to lower-body negative pressure during deficiency.\nCondition category: nutrient_deficiency\nnutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The blood vessels responded less strongly to some constricting signals during shortage.\norganism: Homo sapiens\ntissue_or_cell_type: Human blood or whole-person endpoints\nexperimental_model: Five volunteers studied after three months of vitamin C deprivation and again after four months of repletion.\nlimitations: Does not isolate endothelial, smooth-muscle or collagen mechanisms.\nexposure: Clinical scurvy; forearm blood flow, pressure, catecholamines and responses to lower-body negative pressure, norepinephrine and tyramine.\n[c-abboud1970] Autonomic reflexes and vascular reactivity in experimental scurvy in man (1970). https://pubmed.ncbi.nlm.nih.gov/5411783/ DOI: 10.1172/jci106239","model_system":"Five volunteers studied after three months of vitamin C deprivation and again after four months of repletion.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [c-abboud1970] Autonomic reflexes and vascular reactivity in experimental scurvy in man (1970). https://pubmed.ncbi.nlm.nih.gov/5411783/ DOI: 10.1172/jci106239","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"fa811221-13bd-5c10-adc1-eaf097c7703c","stable_key":"import-cb568d28-484a-5c2e-9fcc-2d780358e514","title":"Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"b7fd83f956abb81855f2ea23199ba14e465cd91f4a2ac560277ec21ddafd7bfc","revision_id":"6cde9bbb-d712-5746-82a6-85b144253efa","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}