Imaging-Analyse dopaminerger Wirkungen am olfaktorischen Nerven von Xenopus-laevis-Larven
Imaging analysis of dopaminergic effects on the olfactory nerv of xenopus laevis tadpoles.
by Eiko Baßfeld
Date of Examination:2013-11-07
Date of issue:2013-11-05
Advisor:Prof. Dr. Dr. Detlev Schild
Referee:Prof. Dr. Detlev Schild
Referee:Prof. Dr. Tim Gollisch
Referee:Prof. Dr. Patricia Virsik-Köpp
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EnglishPreviously it has been demonstrated that dopamine (DA) reduces odor-induced calcium (Ca2+) responses in olfactory receptor neurons in Xenopus laevis tadpoles. This thesis was undertaken to investigate on dopaminergic effects during odor-stimulation in the olfactory nerve (ON). Therefor I established confocal laser imaging of slice preparations of Xenopus laevis tadpoles to record odor-induced Ca2+-response in the ON precisely. Futhermore I found that 15µM-, 25µM-, 50µM-DA reversibly suppresses odor-induced Ca2+-response in the ON. Simultaneously I demonstrated that D2 dopamine receptor (D2R) agonist quinpirole (25µM, 100µM) also reduces Ca2+ transient. The effects of DA was reversed by adding the D2R antagonist sulpiride (100µM, 400µM). It was concluded that the main effects of DA were mediate by D2R. Anymore immunhistochemical dyes has shown tyrosinhydroxylase, a well-established marker on DA metabolism, located in the olfactory ensheating glia cells. Futhermore there was strong evidence that D2R is located at neuronal structures in the ON. These results suggest a neuron-glia interaction within the dopaminergic system in the ON, which maybe point out a process of neuroprotection.
Keywords: dopamine; olfactory; neuroprotection; olfactory nerve; olfactory system; calcium imaging; Xenopus laevis
Schlagwörter: Dopamin; Olfaktorik; Kalzium-Imaging; Xenopus laevis; olfaktorischer Nerv; Neuroprotektion