Component

Photoactivated rhodopsin

Light-activated RHO photopigment state, distinguished from inactive rhodopsin.

3 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What it acts on

  1. Rod calcium-flux recordings showed that illumination reduces outer-segment free calcium as entry falls while extrusion continues.

    Photoactivated rhodopsin → Rod outer-segment free calcium concentration source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    The vitamin A chromophore-initiated electrical response changes calcium signaling inside the rod.
    experimental_model
    Calcium influx/efflux measurements during illumination
    limitations
    Not a claim that dietary calcium intake determines rod calcium transients.
    nutrient_topic
    Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
    organism
    Bufo marinus
    plain_language
    The light response lowers intracellular calcium, providing a recovery signal.
    primary_references
    [yau-1985] Light-induced reduction of cytoplasmic free calcium in retinal rod outer segment (1985). https://pubmed.ncbi.nlm.nih.gov/2578628/ DOI: 10.1038/313579a0
    tissue_or_cell_type
    Rod outer segment

    Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 949–959

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Calcium influx/efflux measurements during illumination · source_derived_draft · unverified_draft

    ### a-vision-light-calcium Rod calcium-flux recordings showed that illumination reduces outer-segment free calcium as entry falls while extrusion continues. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: The light response lowers intracellular calcium, providing a recovery signal. organism: Bufo marinus tissue_or_cell_type: Rod outer segment experimental_model: Calcium influx/efflux measurements during illumination limitations: Not a claim that dietary calcium intake determines rod calcium transients. cross_nutrient: The vitamin A chromophore-initiated electrical response changes calcium signaling inside the rod. [yau-1985] Light-induced reduction of cytoplasmic free calcium in retinal rod outer segment (1985). https://pubmed.ncbi.nlm.nih.gov/2578628/ DOI: 10.1038/313579a0
    Complete structured claim and evidence

  2. Photoactivated rhodopsin catalyzed GDP-to-GTP nucleotide exchange on transducin in reconstituted bovine rod preparations.

    Photoactivated rhodopsin → Rod transducin heterotrimer source_derived_draftungraded
    Experimental context and source evidence
    experimental_model
    Purified protein reconstitution
    limitations
    Biochemical amplification is not a nutritional dose response.
    nutrient_topic
    Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
    organism
    Bos taurus
    plain_language
    Activated pigment switches transducin into its signaling state.
    primary_references
    [fung-1981] Flow of information in the light-triggered cyclic nucleotide cascade of vision (1981). https://pubmed.ncbi.nlm.nih.gov/6264430/ DOI: 10.1073/pnas.78.1.152
    tissue_or_cell_type
    Rod outer-segment protein system

    Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 905–914

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified protein reconstitution · source_derived_draft · unverified_draft

    ### a-vision-transducin-exchange Photoactivated rhodopsin catalyzed GDP-to-GTP nucleotide exchange on transducin in reconstituted bovine rod preparations. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Activated pigment switches transducin into its signaling state. organism: Bos taurus tissue_or_cell_type: Rod outer-segment protein system experimental_model: Purified protein reconstitution limitations: Biochemical amplification is not a nutritional dose response. [fung-1981] Flow of information in the light-triggered cyclic nucleotide cascade of vision (1981). https://pubmed.ncbi.nlm.nih.gov/6264430/ DOI: 10.1073/pnas.78.1.152
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Light activation changes rhodopsin-bound 11-cis-retinal into its all-trans geometry, coupled to receptor activation.

    11-cis-retinal → All-trans-retinal source_derived_draftungraded
    Experimental context and source evidence
    experimental_model
    Solid-state NMR before/after illumination
    limitations
    Bound chromophore conversion precedes release of free retinal.
    nutrient_topic
    Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
    organism
    Bos taurus
    plain_language
    A photon changes the bound retinoid shape and starts the signal.
    primary_references
    [grobner-2000] Observations of light-induced structural changes of retinal within rhodopsin (2000). https://www.nature.com/articles/35015604 DOI: 10.1038/35015604
    tissue_or_cell_type
    Purified rhodopsin

    Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 655–664

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Solid-state NMR before/after illumination · source_derived_draft · unverified_draft

    ### a-vision-photoisomerization Light activation changes rhodopsin-bound 11-cis-retinal into its all-trans geometry, coupled to receptor activation. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: A photon changes the bound retinoid shape and starts the signal. organism: Bos taurus tissue_or_cell_type: Purified rhodopsin experimental_model: Solid-state NMR before/after illumination limitations: Bound chromophore conversion precedes release of free retinal. [grobner-2000] Observations of light-induced structural changes of retinal within rhodopsin (2000). https://www.nature.com/articles/35015604 DOI: 10.1038/35015604
    Complete structured claim and evidence

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

    This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.

    Evidence, AI assistance and curation standards