Evidence map›Paper›PMID 38537648›Full record

ArticleBrain : a journal of neurology2024

Ophthalmate is a new regulator of motor functions via CaSR: implications for movement disorders.

Sammy Alhassen, Derk Hogenkamp, Hung Anh Nguyen, Saeed Al Masri, Geoffrey W Abbott, Olivier Civelli, Amal Alachkar

Open access · bronzeAbstract read
In one paragraph

Article in Brain : a journal of neurology, 2024. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
3citing papers in PubMed, 1 pooled it
1.8field-weighted citation impact, top 15% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

3 citing papers in PubMed, 1 synthesis or guideline pooled it, 5 citations in OpenAlex.

  1. Pooled it
  2. Organosulfur Compounds: Potential Therapeutics for Parkinson's Disease.CNS & neurological disorders drug targets · 2026
    Review
  3. Levodopa treatment: impacts and mechanisms throughout Parkinson's disease progression.Journal of neural transmission (Vienna, Austria : 1996) · 2025
    Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors at 1 institution in 1 country.

Sammy AlhassenDepartment of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University of California Irvine, Irvine, CA 92697, USA.
Derk HogenkampDepartment of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University of California Irvine, Irvine, CA 92697, USA.
Hung Anh NguyenDepartment of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University of California Irvine, Irvine, CA 92697, USA.
Saeed Al MasriDepartment of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University of California Irvine, Irvine, CA 92697, USA.
Geoffrey W AbbottBioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California Irvine, Irvine, CA 92697, USA.
Olivier CivelliDepartment of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University of California Irvine, Irvine, CA 92697, USA.
Amal AlachkarDepartment of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University of California Irvine, Irvine, CA 92697, USA.ORCID 0000-0002-5365-1726
University of California, Irvine · US

Funding

Therapeutic small molecule modulation of Kv channelsR01NS107671 · NINDS · UNIVERSITY OF CALIFORNIA-IRVINE · PI Geoffrey W Abbott · 2019 to 2026
$3.1M
Eric L. and Lila D. Nelson Chair in NeuropharmacologyNINDS NIH HHS NS107671NINDS NIH HHS R01 NS107671US National Institutes of Health
6 · The paper itself

Abstract

Dopamine's role as the principal neurotransmitter in motor functions has long been accepted. We broaden this conventional perspective by demonstrating the involvement of non-dopaminergic mechanisms. In mouse models of Parkinson's disease, we observed that L-DOPA elicited a substantial motor response even when its conversion to dopamine was blocked by inhibiting the enzyme aromatic amino acid decarboxylase (AADC). Remarkably, the motor activity response to L-DOPA in the presence of an AADC inhibitor (NSD1015) showed a delayed onset, yet greater intensity and longer duration, peaking at 7 h, compared to when L-DOPA was administered alone. This suggests an alternative pathway or mechanism, independent of dopamine signalling, mediating the motor functions. We sought to determine the metabolites associated with the pronounced hyperactivity observed, using comprehensive metabolomics analysis. Our results revealed that the peak in motor activity induced by NSD1015/L-DOPA in Parkinson's disease mice is associated with a surge (20-fold) in brain levels of the tripeptide ophthalmic acid (also known as ophthalmate in its anionic form). Interestingly, we found that administering ophthalmate directly to the brain rescued motor deficits in Parkinson's disease mice in a dose-dependent manner. We investigated the molecular mechanisms underlying ophthalmate's action and discovered, through radioligand binding and cAMP-luminescence assays, that ophthalmate binds to and activates the calcium-sensing receptor (CaSR). Additionally, our findings demonstrated that a CaSR antagonist inhibits the motor-enhancing effects of ophthalmate, further solidifying the evidence that ophthalmate modulates motor functions through the activation of the CaSR. The discovery of ophthalmate as a novel regulator of motor function presents significant potential to transform our understanding of brain mechanisms of movement control and the therapeutic management of related disorders.

Indexed as

LevodopaMotor ActivityReceptors, Calcium-SensingAnimalsDisease Models, AnimalDopamineHumansMaleMiceMice, Inbred C57BLMovement DisordersOligopeptidesDopamineLevodopaOligopeptidesReceptors, Calcium-SensingCaSRdopaminemotorophthalmateParkinson’s disease

Identifiers

PMID38537648
PMCPMC11449132
OpenAlexW4393236258

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.