Autofluorescence Spectrofluorometry of central nervous system (CNS) neuromediators

Abstract

Autofluorescence spectroscopy potential is confirmed as a suitable technique for the direct measurement of neurotransmitters.

Designing sensitive and selective polymer/enzyme composite biosensors for brain monitoring in vivo

“…However, measuring real-time chemical events in the living brain is a supreme technical challenge, even in animal models, and involves many biocompatibility issues. A growing number of analytical methodologies are being developed, including sampling [1,2], spectroscopic [3] and electrochemical [4][5][6], to study neurochemical dynamics in the intact brain. One such set of techniques involves the in-situ detection of substances in brain extracellular fluid (ECF) using implanted biosensors.…”

In vivo autofluorescence spectrofluorometry of central serotonin

“…The same excitation performed on ex vivo samples (hippocampal tissue slices and homogenate) revealed spectral changes attributable to the increase in the amount of 5-HT supplied as exogenous compound or induced in the rats by specific treatments. These data were supported by parallel experiments using conventional voltammetry (Crespi et al, 2004). All these features supported the development of conventional fluorometric techniques to monitor 5-HT levels directly in biological tissues.…”

“…This is a very short-wavelength spectral region, a condition that, with reference to the optical properties of biological tissues, may limit in situ measurements. To overcome this limitation, 5-HT-autofluorescence properties in longer wavelength spectral regions have been investigated (Tan et al, 1995;Crespi et al, 2004). The benefits associated with decreased light scattering and competitive absorption at longer wavelengths can offset the poor absorption properties at these wavelengths.…”

“…As already described in detail (Crespi et al, 2004), 5-HT, as a pure compound in solution, exhibits two main absorption bands at about 280 and 300 nm, with minor absorption bands in the 330-390 nm, 450-490 nm, and 510-580 nm regions. At very high concentrations (i.e.…”

“…The latter technique, despite weak signals, was successfully applied in the near-UV-vis fluorescence microscopy to the in situ imaging study of the uptake and depletion of neurotransmitters in astrocytes (Tan et al, 1995(Tan et al, , 1997Yeung, 1999). The excitation and emission of 5-HT at longer wavelengths have been recently characterized in more details (Crespi et al, 2004). 5-HT in solution showed minor absorption bands in the 340-590 nm spectral region, and an excitation band in the 310-370 nm region, particularly evident for high 5-HT concentrations.…”