Preserved noradrenergic function in Parkinson's disease patients with rest tremor

Martin B Kinnerup*, Michael Sommerauer, Malene F Damholdt, Jeppe L Schaldemose, Rola Ismail, Astrid J Terkelsen, Kristian Stær, Allan Hansen, Tatyana D Fedorova, Karoline Knudsen, Casper Skjærbæk, Per Borghammer, Nicola Pavese, David J Brooks, Adjmal Nahimi

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review


Noradrenergic neurotransmission may play an important role in tremor modulation through its innervation of key structures of the central tremor circuits. Here, Parkinson's disease (PD) patients with (PDT+) or without (PDT-) rest tremor had 11C-methylreboxetine(11C-MeNER) positron emission tomography (PET) to test the hypothesis that noradrenaline terminal function was relatively preserved in PDT+ compared to PDT-.

METHODS: Sixty-five PD patients and 28 healthy controls (HC) were scanned with 11C-MeNER PET. Patients were categorized as PDT+ if subscores in UPDRS-III item 3 or MDS-UPDRS-III item 17 was ≥2; remaining were categorized as PDT-. Simplified reference tissue model 2 distribution volume ratios (DVR) were calculated for thalamus, dorsal and median raphe, locus coeruleus (LC) and red nucleus using time activity curves (TACs) obtained from volumes of interest (VOI). Data were statistically interrogated with a general linear mixed model using 'region', and 'group' as factors and the interaction of 'region x group' was examined.

RESULTS: Tremor positive PD patients had a significantly higher mean 11C-MeNER DVR compared to PDT- in LC and thalamus. The PDT+ mean LC DVR was similar to that of HC. PDT+ mean 11C-MeNER DVRs were significantly lower than HC in the dorsal raphe while the PDT- group showed significantly lower mean 11C-MeNER DVR across all regions compared to HC.

CONCLUSION: While both PD T+ and PD T- groups showed a significant loss of noradrenaline terminal function compared to controls, noradrenergic neurons were relatively preserved in PDT+ in LC and thalamus. The greater loss of noradrenergic transporters in PDT- in LC and thalamus compared with PDT+ is in line with earlier in-vitro studies and could potentially contribute to their tremor negative phenotype.

Original languageEnglish
Article number105295
JournalNeurobiology of Disease
Number of pages8
Publication statusPublished - May 2021


  • C-MeNER
  • Noradrenaline transporter
  • Parkinson's disease
  • Positron emission tomography (PET)
  • Tremor


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