{"id":"d6140aee-b9f6-533f-ae05-670c55fdf73c","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:c-scurvy-catecholamine-reflex-boundary","predicate":"depletion_did_not_significantly_lower_plasma_catecholamines","statement":"Resting plasma catecholamines and hemodynamic measurements did not change significantly after correction; reflex tachycardia and bradycardia were similar in the deficient and repleted studies.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"0ed28240-c360-5ac1-b0a4-2a4fb1072148","mechanism_event_label":"An enzyme’s vitamin C requirement did not translate into complete failure of the human stress-signal system.","subject":{"id":"da1a7137-08f2-5a36-8bb6-377fbd32e327","slug":"vitamin-c","display_name":"Vitamin C","entity_type_key":"chemical_species"},"object":{"id":"d45f0ecb-85ef-5ca6-b7e0-88f644ba4f22","slug":"plasma-catecholamine-concentration","display_name":"Plasma catecholamine concentration","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"0ed28240-c360-5ac1-b0a4-2a4fb1072148","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:c-scurvy-catecholamine-reflex-boundary-event","event_type":"observed_intervention","label":"An enzyme’s vitamin C requirement did not translate into complete failure of the human stress-signal system.","description":"Resting plasma catecholamines and hemodynamic measurements did not change significantly after correction; 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unverified.","entity":null}],"evidence":[{"id":"a2231cf7-793f-5512-8d5b-6a702395193c","evidence_kind":"source_excerpt","locator":"Lines 1541-1552","start_line":1541,"end_line":1552,"excerpt":"### c-scurvy-catecholamine-reflex-boundary\nResting plasma catecholamines and hemodynamic measurements did not change significantly after correction; reflex tachycardia and bradycardia were similar in the deficient and repleted studies.\nCondition category: nutrient_deficiency\nnutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: An enzyme’s vitamin C requirement did not translate into complete failure of the human stress-signal system.\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: Plasma catecholamines do not measure all neuronal stores or DBH flux; limited power in five participants.\nexposure: Clinical scurvy; forearm blood flow, pressure, catecholamines and responses to lower-body negative pressure, norepinephrine and tyramine.\ncross_nutrient: Clinical boundary for the copper/ascorbate-dependent dopamine beta-hydroxylase pathway.\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. 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