Regional distribution of manganese found in the brain after injection of a single dose of manganese-based contrast agents.
Gallez B, Baudelet C, Geurts M
Laboratory of Medicinal Chemistry and Radiopharmacy, Catholic University of Louvain, Brussels, Belgium. Gallez@cmfa.ucl.ac.be
Manganese (Mn) complexes are unstable and dissociate in vivo. Because
of the release of this metal, there exists some concern about the potential
long-term neurotoxicity associated with the use of Mn-based contrast agents.
This latter problem arises because manganese is known to accumulate in
specific regions of the brain of people intoxicated by this metal. It was
previously demonstrated that Mn can accumulate in the mice brain after
administration of 5 micromol/kg of MnCl2, Mn-diethylenetriaminepentaacetate
(Mn-DTPA), or Mn-dipyridoxal diphosphate (Mn-DPDP). In order to better
characterize the behavior of Mn complexes after administration, this study
assesses the regional distribution of Mn in the brain after i.v. injection
of a single dose of MnCl2 or Mn-DTPA. Male Wistar rats received an i.v.
injection of 5 micromol/kg of 54Mn as MnCl2 or Mn-DTPA. The rats were killed
at one and two weeks post exposure. The distribution of the radioactivity
in the slices was monitored by autoradiography. For both MnCl2 or Mn-DTPA,
we observed that the radioactivity was dispersed in the entire brain, but
the radioactivity was higher in several regions. No difference was observed
between MnCl2 or Mn-DTPA in the regional distribution of Mn, and no difference
was observed between the two times of exposure (1 week or 2 weeks). The
uptake of Mn was minimal in corpus callosum. Maximal Mn concentration was
observed in the hippocampal region, thalamus, colliculi, amygdala, olfactory
nuclei, and cerebellum.
PMID: 9858278, UI: 99073989