Highlighting manganese dynamics in the nervous system of Aplysia californica using MEMRI at ultra-high field.
NeuroImage. 2013-08-01; 76: 264-271
Lire sur PubMed
1. Neuroimage. 2013 Aug 1;76:264-71. doi: 10.1016/j.neuroimage.2013.03.022. Epub
2013 Mar 22.
Highlighting manganese dynamics in the nervous system of Aplysia californica
using MEMRI at ultra-high field.
Jelescu IO(1), Nargeot R, Le Bihan D, Ciobanu L.
(1)NeuroSpin, Commissariat à l’Energie Atomique et aux Energies Alternatives,
91191 Gif-sur-Yvette, France.
Exploring the pathways of manganese (Mn(2+)) transport in the nervous system
becomes of interest as many recent studies use Mn(2+) as a neural tract tracer in
mammals. In this study, we performed manganese enhanced MRI (MEMRI) at 17.2 T on
the buccal ganglia of Aplysia californica. The main advantage of this model over
mammalian systems is that it contains networks of large identified neurons. Using
Mn(2+) retrograde transport along selected nerves, we first validated the mapping
of motor neurons’ axonal projections into peripheral nerves, previously obtained
from optical imaging (Morton et al., 1991). This protocol was found not to alter
the functional properties of the neuronal network. Second, we compared the Mn(2+)
dynamics inside the ganglia in the presence or absence of chemical stimulation.
We found that 2h of stimulation with the modulatory transmitter dopamine
increased the extent of areas of intermediate signal enhancement caused by
manganese accumulation. In the absence of dopamine, an overall decrease of the
enhanced areas in favor of non-enhanced areas was found, as a result of natural
Mn(2+) washout. This supports the hypothesis that, upon activation, Mn(2+) is
released from labeled neurons and captured by other, initially unlabeled,
neurons. However, the latter could not be clearly identified due to lack of
sensitivity and multiplicity of possible pathways starting from labeled cells.
Nonetheless, the Aplysia buccal ganglia remain a well-suited model for attempting
to visualize Mn(2+) transport from neuron to neuron upon activation, as well as
for studying dopaminergic modulation in a motor network.
Copyright © 2013 Elsevier Inc. All rights reserved.
PMID: 23523801 [Indexed for MEDLINE]