In vivomonitoring of the transfer kinetics of trace elements in animal brains with hyphenated inductively coupled plasma mass spectrometry techniques

Abstract

The roles of metal ions to sustain normal function and to cause dysfunction of neurological systems have been confirmed by various studies. However, because of the lack of adequate analytical method to monitor the transfer kinetics of metal ions in the brain of a living animal, research on the physiopathological roles of metal ions in the CNS remains in its early stages and more analytical efforts are still needed. To explicitly model the possible links between metal ions and physiopathological alterations, it is essential to develop in vivo monitoring techniques that can bridge the gap between metalloneurochemistry and neurophysiopathology. Although inductively coupled plasma mass spectrometry (ICP-MS) is a very powerful technique for multiple trace element analyses, when dealing with chemically complex microdialysis samples, the detection capability is largely limited by instrumental sensitivity, selectivity, and contamination that arise from the experimental procedure. As a result, in recent years several high efficient and clean on-line sample pretreatment systems have been developed and combined with microdialysis and ICP-MS for the continuous and in vivo determination of the concentration-time profiles of metal ions in the extracellular space of rat brain. This article reviews the research relevant to the development of analytical techniques for the in vivo determination of dynamic variation in the concentration levels of metal ions in a living animal.

Effects of tetrathiomolybdate and penicillamine on brain hydroxyl radical and free copper levels: A microdialysis study in vivo

“…In this study, the free copper levels in the brain are been assayed by microdialysis in vivo [23]. Several methods were developed to measure the brain's oxidative stress in WD and other processes [24,25].…”

In vivo neurochemical measurements in cerebral tissues using a droplet-based monitoring system

“…Although less studied, transition metal elements are also known to play critical roles in synaptic transmission, and might be implicated in neurological diseases 8 , 33 . For instance, Fe is a cofactor for a variety of enzymes responsible for the synthesis of dopamine in synapses 8 , 34 , 35 , Cu is hypothesized to inhibit the voltage-gated calcium channel of synapses and is responsible for impaired neurotransmission when its concentration in too high 8 , 36 , 37 while Zn 2+ is involved in the release of the glutamate and γ -aminobutyric acid (GABA) release 8 , 38 – 40 . Although our system is compatible to different types of surface-based analysis, LA-ICP-MS is a promising method for neuroscience applications since it enables to draw a picture of trace elements distribution in a brain section at a given time.…”

“…The perfusate is then collected and analyzed. The large acceptance of this method by the neuroscientist community is due to its relative simple operation and the statement that it preserves anatomical and functional integrity of the surrounding tissues 8 . However, microdialysis catheters have several limitations, starting with a relatively large exchange membrane area (diameter of 400 μm, length of 1−4 mm) limiting spatial resolution 9 – 11 .…”

“…Similarly, mass transport is limited by the size exclusion of the membrane which prevents large molecules such as proteins to be collected 13 . Besides the limited spatial resolution and associated tissue damages, the temporal resolution of microdialysis probe is usually limited to 10−20 min by the perfusion rate (typically 1 μL/min) and the associated analysis method 8 . With such a limitation, the method is probably only suited for observing long term kinetics of pharmacological agents and their effects in the brain 14 .…”

Bioimaging of metals in brain tissue from micrometre to nanometre scale by laser ablation inductively coupled plasma mass spectrometry: State of the art and perspectives

“…The role of metal ions in neurodegenerative diseases in brain is discussed in several studies [30,[59][60][61]. From the literature is known that:…”