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.
Crespi
Francesco
F
Department of Biology, Psychiatry C.E.D.D., GlaxoSmithKline S.p.A., Verona, Italy.
Croce
Anna C
AC
Fiorani
Sabrina
S
Masala
Barbara
B
Heidbreder
Christian
C
Bottiroli
Giovanni
G
D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D001923:Brain Chemistry / Q000502:physiology*; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D004566:Electrodes / Q000639:trends; D005336:Fiber Optic Technology / Q000639:trends; D005453:Fluorescence; D005473:Fluoxetine / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009448:Neurochemistry / Q000379:methods*; D051381:Rats; D012701:Serotonin / Q000032:analysis* / Q000378:metabolism; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013347:Subcellular Fractions
D006916:5-Hydroxytryptophan; D005473:Fluoxetine; D012701:Serotonin; D017367:Selective Serotonin Reuptake Inhibitors