In vivo autofluorescence spectrofluorometry of central serotonin

The autofluorescence properties of serotonin (5-HT) were investigated by light spectrofluorometry in in vitro, ex vivo and in vivo experiments. Ex vivo samples were prepared from rat brain regions containing serotonin (5-HT) i.e. cortex, striatum, hippocampus. Rats were untreated (controls) or previously submitted to chronic behavioural or pharmacological treatments known to affect endogenous 5-HT levels. Autofluorescence analysis (excitation: 366 nm) on hippocampus homogenates supplied with exogenous 5-HT revealed spectral alterations attributable to changes of endogenous 5-HT levels. In vivo, real time fluorescence studies were performed via a 50 microm diameter optic fiber probe stereotaxically implanted into selected brain areas of anaesthetised rats treated with fluoxetine or 5-OH-tryptophan. All autofluorescence data were consistent with those obtained in parallel experiments performed with ex vivo or in vivo voltammetry, confirming that auto-fluorescence spectroscopy is a suitable technique for the direct assessment of fluorescent neurotransmitters. This is a reliable evidence of the in vivo application of spectroscopy together with optic fiber probe for in vivo, in situ and real time measurement of 5-HT in discrete brain areas.

[1]  Romain Meeusen,et al.  Differential effects of restraint stress on hippocampal 5-HT metabolism and extracellular levels of 5-HT in streptozotocin-diabetic rats , 1997, Brain Research.

[2]  C. Montigny,et al.  Current advances and trends in the treatment of depression. , 1994, Trends in pharmacological sciences.

[3]  E. Yeung.  Following single cell dynamics with native fluorescence microscopy. , 1999, Analytical chemistry.

[4]  D. Wong,et al.  Prozac (fluoxetine, Lilly 110140), the first selective serotonin uptake inhibitor and an antidepressant drug: twenty years since its first publication. , 1995, Life sciences.

[5]  E. Yeung,et al.  Imaging Neurotransmitter Uptake and Depletion in Astrocytes , 1997 .

[6]  A. Sakurada,et al.  Diagnostic results before and after introduction of autofluorescence bronchoscopy in patients suspected of having lung cancer detected by sputum cytology in lung cancer mass screening. , 2001, Lung cancer.

[7]  C. Pietra,et al.  Middle cerebral artery occlusion alters neurotransmitter activities in ipsilateral and contralateral rat brain regions: an ex vivo voltammetric study , 1997, Neuroscience Letters.

[8]  I. Lucki,et al.  Effects of acute and repeated administration of antidepressant drugs on extracellular levels of 5-hydroxytryptamine measured in vivo. , 1995, The Journal of pharmacology and experimental therapeutics.

[9]  W. Webb,et al.  Live tissue intrinsic emission microscopy using multiphoton-excited native fluorescence and second harmonic generation , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[10]  F. Crespi.  In vivo voltammetry with micro-biosensors for analysis of neurotransmitter release and metabolism , 1990, Journal of Neuroscience Methods.

[11]  Giovanni Bottiroli,et al.  Autofluorescence Spectrofluorometry of central nervous system (CNS) neuromediators , 2004, Lasers in surgery and medicine.

[12]  Renato Marchesini,et al.  Ex vivo optical properties of human colon tissue , 1994, Lasers in surgery and medicine.

[13]  Francesco Crespi,et al.  Carbon fibre micro-electrodes for concomitant in vivo electrophysiological and voltammetric measurements: no reciprocal influences , 1995, Neuroscience Letters.

[14]  Sidney Udenfriend,et al.  Fluorescence assay in biology and medicine , 1962 .

[15]  R. Marchesini,et al.  Natural fluorescence of normal and neoplastic human colon: A comprehensive “ex vivo” study , 1995, Lasers in surgery and medicine.

[16]  Sharon Thomsen,et al.  Spectroscopic diagnosis of cervical intraepithelial neoplasia (CIN) in vivo using laser‐induced fluorescence spectra at multiple excitation wavlengths , 1996, Lasers in surgery and medicine.

[17]  K Svanberg,et al.  In vivo fluorescence imaging for tissue diagnostics. , 1997, Physics in medicine and biology.

[18]  M Fitzmaurice,et al.  Laser induced fluorescence spectroscopy of normal and atherosclerotic human aorta using 306–310 nm excitation , 1990, Lasers in surgery and medicine.

[19]  C Bellman,et al.  Fundus autofluorescence and development of geographic atrophy in age-related macular degeneration. , 2001, Investigative ophthalmology & visual science.

[20]  E. Yeung,et al.  Neurotransmitter imaging in living cells based on native fluorescence detection. , 1995, Analytical chemistry.

[21]  Giovanni Bottiroli,et al.  Diagnostic Potential of Autofluorescence for an Assisted Intraoperative Delineation of Glioblastoma Resection Margins¶ , 2003, Photochemistry and photobiology.

[22]  A F Gmitro,et al.  Measurement depth of laser-induced tissue fluorescence with application to laser angioplasty. , 1988, Applied optics.

[23]  F. Crespi.  In vivo voltammetry and concomitant electrophysiology at a single micro-biosensor to analyse ischaemia, depression and drug dependence , 2002, Journal of Neuroscience Methods.

[24]  Rafael Yuste,et al.  Fluorescence microscopy today , 2005, Nature Methods.

[25]  B. Wilson,et al.  In Vivo Fluorescence Spectroscopy and Imaging for Oncological Applications , 1998, Photochemistry and photobiology.

[26]  J. Aubin.  Autofluorescence of viable cultured mammalian cells. , 1979, The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society.

[27]  G. Bottiroli,et al.  Dependence of Fibroblast Autofluorescence Properties on Normal and Transformed Conditions. Role of the Metabolic Activity , 1999, Photochemistry and photobiology.

[28]  W. Webb,et al.  Measuring Serotonin Distribution in Live Cells with Three-Photon Excitation , 1997, Science.