Metabolism of hyperpolarised [1–13C]pyruvate in awake and anaesthetised rat brains

Viivi Hyppönen, Petteri Stenroos, Riikka Nivajärvi, Jan Henrik Ardenkjær-Larsen, Olli Gröhn, Jaakko Paasonen, Mikko I. Kettunen*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review


The use of hyperpolarised 13C pyruvate for nononcological neurological applications has not been widespread so far, possibly due to delivery issues limiting the visibility of metabolites. First proof-of-concept results have indicated that metabolism can be detected in human brain, and this may supersede the results obtained in preclinical settings. One major difference between the experimental setups is that preclinical MRI/MRS routinely uses anaesthesia, which alters both haemodynamics and metabolism. Here, we used hyperpolarised [1–13C]pyruvate to compare brain metabolism in awake rats and under isoflurane, urethane or medetomidine anaesthesia. Spectroscopic [1–13C]pyruvate time courses measured sequentially showed that pyruvate-to-bicarbonate and pyruvate-to-lactate labelling rates were lower in isoflurane animals than awake animals. An increased bicarbonate-to-lactate ratio was observed in the medetomidine group compared with other groups. The study shows that hyperpolarised [1–13C]pyruvate experiments can be performed in awake rats, thus avoiding anaesthesia-related issues. The results suggest that haemodynamics probably dominate the observed pyruvate-to-metabolite labelling rates and area-under-time course ratios of referenced to pyruvate. On the other hand, the results obtained with medetomidine suggest that the ratios are also modulated by the underlying cerebral metabolism. However, the ratios between intracellular metabolites were unchanged in awake compared with isoflurane-anaesthetised rats.

Original languageEnglish
Article numbere4635
JournalNMR in Biomedicine
Issue number2
Number of pages10
Publication statusPublished - 2022


  • Blood–brain barrier
  • Isoflurane
  • Medetomidine
  • Urethane


Dive into the research topics of 'Metabolism of hyperpolarised [1–13C]pyruvate in awake and anaesthetised rat brains'. Together they form a unique fingerprint.

Cite this