Limits...
Neurochemical measurements in the zebrafish brain.

Jones LJ, McCutcheon JE, Young AM, Norton WH - Front Behav Neurosci (2015)

Bottom Line: In this study we have used in vitro FSCV to measure the release of analytes in the adult zebrafish telencephalon.We compare different stimulation methods and present a characterization of neurochemical changes in the wild-type zebrafish brain.This study represents the first FSCV recordings in zebrafish, thus paving the way for neurochemical analysis of the fish brain.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroscience, Psychology and Behaviour, University of Leicester Leicester, UK.

ABSTRACT
The zebrafish is an ideal model organism for behavioral genetics and neuroscience. The high conservation of genes and neurotransmitter pathways between zebrafish and other vertebrates permits the translation of research between species. Zebrafish behavior can be studied at both larval and adult stages and recent research has begun to establish zebrafish models for human disease. Fast scan cyclic voltammetry (FSCV) is an electrochemical technique that permits the detection of neurotransmitter release and reuptake. In this study we have used in vitro FSCV to measure the release of analytes in the adult zebrafish telencephalon. We compare different stimulation methods and present a characterization of neurochemical changes in the wild-type zebrafish brain. This study represents the first FSCV recordings in zebrafish, thus paving the way for neurochemical analysis of the fish brain.

No MeSH data available.


Related in: MedlinePlus

Comparison of cyclic voltammograms generated by exposing electrodes to mixtures of dopamine, 5-HT, and histamine and pH changes in a flow cell. (A) 1 μM dopamine and 40 μM histamine solutions. (B) 2 μM dopamine and 20 μM histamine solutions. (C) 0.25 μM 5-HT and 40 μM histamine solutions. (D) 0.25 μM 5-HT, 1μM dopamine and 20 μM histamine solutions. (E) Voltammogram resulting from exposing an electrode in a flow cell to 1 μM dopamine and 40 μM histamine in the presence of an acidic pH shift (−0.5 pH units, pH 7.4 → pH 6.9). (F) Voltammogram resulting from exposing an electrode in a flow cell to 80 μM histamine in the presence of an acidic pH shift (−0.25 pH units; pH 7.4 → pH 7.15). (G) Voltammogram resulting from exposing an electrode in a flow cell to 1 μM dopamine and 40 μM histamine in the presence of a basic pH shift (+1.0 pH units, pH 7.4 → pH 8.4). (H) Voltammogram resulting from exposing an electrode in a flow cell to 1 μM 5-HT and 80 μM histamine in the presence of an acidic pH shift (−0.5 pH units, pH 7.4 → pH 6.9). Black lines represent forward scan and red lines reverse scan.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4561813&req=5

Figure 6: Comparison of cyclic voltammograms generated by exposing electrodes to mixtures of dopamine, 5-HT, and histamine and pH changes in a flow cell. (A) 1 μM dopamine and 40 μM histamine solutions. (B) 2 μM dopamine and 20 μM histamine solutions. (C) 0.25 μM 5-HT and 40 μM histamine solutions. (D) 0.25 μM 5-HT, 1μM dopamine and 20 μM histamine solutions. (E) Voltammogram resulting from exposing an electrode in a flow cell to 1 μM dopamine and 40 μM histamine in the presence of an acidic pH shift (−0.5 pH units, pH 7.4 → pH 6.9). (F) Voltammogram resulting from exposing an electrode in a flow cell to 80 μM histamine in the presence of an acidic pH shift (−0.25 pH units; pH 7.4 → pH 7.15). (G) Voltammogram resulting from exposing an electrode in a flow cell to 1 μM dopamine and 40 μM histamine in the presence of a basic pH shift (+1.0 pH units, pH 7.4 → pH 8.4). (H) Voltammogram resulting from exposing an electrode in a flow cell to 1 μM 5-HT and 80 μM histamine in the presence of an acidic pH shift (−0.5 pH units, pH 7.4 → pH 6.9). Black lines represent forward scan and red lines reverse scan.

Mentions: The color- and voltage-plots that we obtained from recordings in the zebrafish telencephalon appeared to be influenced by the release of more than one analyte. We applied combinations of dopamine, 5-HT and histamine and pH changes to the electrode in the flow cell and measured changes in current. A combination of 1 μM dopamine and 40 μM histamine produced a cyclic voltammogram with a small oxidation peak at ~ +0.6 V, a larger oxidation peak at around +1.0 V and three reduction peaks at ~ +0.25, ~ −0.2, and ~ −0.4 V (Figure 6A). A combination of 2 μM dopamine and 20 μM histamine produced a very large oxidation peak at ~ +0.6 V, a second oxidation peak on the reverse scan at ~ +1.0 V and reduction peaks at ~ +0.2, ~ −0.2, and ~ −0.4 V (Figure 6B). Likewise, combining 5-HT and histamine produced a voltammogram with a similar oxidation profile but different reduction profile. A mixture of 0.25 μM 5-HT and 40 μM histamine led to oxidation peaks at ~ +0.6 and ~ +1.0 V and reduction peaks at ~ +0.3, ~0, and ~-0.4 V (Figure 6C). We also examined the current changes produced by mixing all three neurotransmitters. A combination of 0.25 μM 5-HT, 1 μM dopamine and 20 μM histamine produced a current plot with oxidation peaks at ~ +0.6 and ~ +1.0 V and four reduction peaks at ~ +0.2, ~0, ~ −0.2, and ~ −0.4 V (Figure 6D). Together, these data indicate that it should be possible to separate signals composed of these three neurotransmitters, since each individual peak is neither inflated nor altered by the presence of a second compound, apart from the overlapping oxidation peak at ~ +0.6 V for dopamine and 5-HT. However, 5-HT can still be identified by its unique reduction peaks, permitting the visual dissociation of these two transmitters. We explored the possibility that pH changes could be influencing the signals that we recorded in the telencephalon by altering the pH of dopamine, histamine and 5-HT mixtures in a flow cell. A combination of -0.5 pH units, 1 μM dopamine and 40 μM histamine (Figure 6E) produced a cyclic voltammogram similar to the voltammogram obtained ~10 s after high K+ aCSF stimulation (Figure 2D). Altering the pH of histamine alone (80 μM histamine and −0.25 pH units; Figure 6F) provided a good in-vitro representation of the voltammogram for the second analyte obtained with high K+ HEPES-buffered aCSF (Figures 6E,F). Despite not being completely identical, it showed changes in current at ~ +0.2, ~ +1.0, and ~ −0.4 V. A basic change in pH (+1.0 units) coupled to 1 μM dopamine and 40 μM histamine produced a voltammogram with a broad reduction peak around +0.4 V (Figure 6G) but no large reduction peak at ~ −0.4 V (Figures 5E,F) suggesting that the pH change was not likely to be basic. Furthermore, addition of 5-HT to the flow cell mixture also produced a voltammogram with a very different shape (1 μM 5-HT, 80 μM histamine and −0.5 pH units) suggesting that 5-HT was unlikely to have contributed to the analytes measured in the telencephalon (Figure 6H).


Neurochemical measurements in the zebrafish brain.

Jones LJ, McCutcheon JE, Young AM, Norton WH - Front Behav Neurosci (2015)

Comparison of cyclic voltammograms generated by exposing electrodes to mixtures of dopamine, 5-HT, and histamine and pH changes in a flow cell. (A) 1 μM dopamine and 40 μM histamine solutions. (B) 2 μM dopamine and 20 μM histamine solutions. (C) 0.25 μM 5-HT and 40 μM histamine solutions. (D) 0.25 μM 5-HT, 1μM dopamine and 20 μM histamine solutions. (E) Voltammogram resulting from exposing an electrode in a flow cell to 1 μM dopamine and 40 μM histamine in the presence of an acidic pH shift (−0.5 pH units, pH 7.4 → pH 6.9). (F) Voltammogram resulting from exposing an electrode in a flow cell to 80 μM histamine in the presence of an acidic pH shift (−0.25 pH units; pH 7.4 → pH 7.15). (G) Voltammogram resulting from exposing an electrode in a flow cell to 1 μM dopamine and 40 μM histamine in the presence of a basic pH shift (+1.0 pH units, pH 7.4 → pH 8.4). (H) Voltammogram resulting from exposing an electrode in a flow cell to 1 μM 5-HT and 80 μM histamine in the presence of an acidic pH shift (−0.5 pH units, pH 7.4 → pH 6.9). Black lines represent forward scan and red lines reverse scan.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561813&req=5

Figure 6: Comparison of cyclic voltammograms generated by exposing electrodes to mixtures of dopamine, 5-HT, and histamine and pH changes in a flow cell. (A) 1 μM dopamine and 40 μM histamine solutions. (B) 2 μM dopamine and 20 μM histamine solutions. (C) 0.25 μM 5-HT and 40 μM histamine solutions. (D) 0.25 μM 5-HT, 1μM dopamine and 20 μM histamine solutions. (E) Voltammogram resulting from exposing an electrode in a flow cell to 1 μM dopamine and 40 μM histamine in the presence of an acidic pH shift (−0.5 pH units, pH 7.4 → pH 6.9). (F) Voltammogram resulting from exposing an electrode in a flow cell to 80 μM histamine in the presence of an acidic pH shift (−0.25 pH units; pH 7.4 → pH 7.15). (G) Voltammogram resulting from exposing an electrode in a flow cell to 1 μM dopamine and 40 μM histamine in the presence of a basic pH shift (+1.0 pH units, pH 7.4 → pH 8.4). (H) Voltammogram resulting from exposing an electrode in a flow cell to 1 μM 5-HT and 80 μM histamine in the presence of an acidic pH shift (−0.5 pH units, pH 7.4 → pH 6.9). Black lines represent forward scan and red lines reverse scan.
Mentions: The color- and voltage-plots that we obtained from recordings in the zebrafish telencephalon appeared to be influenced by the release of more than one analyte. We applied combinations of dopamine, 5-HT and histamine and pH changes to the electrode in the flow cell and measured changes in current. A combination of 1 μM dopamine and 40 μM histamine produced a cyclic voltammogram with a small oxidation peak at ~ +0.6 V, a larger oxidation peak at around +1.0 V and three reduction peaks at ~ +0.25, ~ −0.2, and ~ −0.4 V (Figure 6A). A combination of 2 μM dopamine and 20 μM histamine produced a very large oxidation peak at ~ +0.6 V, a second oxidation peak on the reverse scan at ~ +1.0 V and reduction peaks at ~ +0.2, ~ −0.2, and ~ −0.4 V (Figure 6B). Likewise, combining 5-HT and histamine produced a voltammogram with a similar oxidation profile but different reduction profile. A mixture of 0.25 μM 5-HT and 40 μM histamine led to oxidation peaks at ~ +0.6 and ~ +1.0 V and reduction peaks at ~ +0.3, ~0, and ~-0.4 V (Figure 6C). We also examined the current changes produced by mixing all three neurotransmitters. A combination of 0.25 μM 5-HT, 1 μM dopamine and 20 μM histamine produced a current plot with oxidation peaks at ~ +0.6 and ~ +1.0 V and four reduction peaks at ~ +0.2, ~0, ~ −0.2, and ~ −0.4 V (Figure 6D). Together, these data indicate that it should be possible to separate signals composed of these three neurotransmitters, since each individual peak is neither inflated nor altered by the presence of a second compound, apart from the overlapping oxidation peak at ~ +0.6 V for dopamine and 5-HT. However, 5-HT can still be identified by its unique reduction peaks, permitting the visual dissociation of these two transmitters. We explored the possibility that pH changes could be influencing the signals that we recorded in the telencephalon by altering the pH of dopamine, histamine and 5-HT mixtures in a flow cell. A combination of -0.5 pH units, 1 μM dopamine and 40 μM histamine (Figure 6E) produced a cyclic voltammogram similar to the voltammogram obtained ~10 s after high K+ aCSF stimulation (Figure 2D). Altering the pH of histamine alone (80 μM histamine and −0.25 pH units; Figure 6F) provided a good in-vitro representation of the voltammogram for the second analyte obtained with high K+ HEPES-buffered aCSF (Figures 6E,F). Despite not being completely identical, it showed changes in current at ~ +0.2, ~ +1.0, and ~ −0.4 V. A basic change in pH (+1.0 units) coupled to 1 μM dopamine and 40 μM histamine produced a voltammogram with a broad reduction peak around +0.4 V (Figure 6G) but no large reduction peak at ~ −0.4 V (Figures 5E,F) suggesting that the pH change was not likely to be basic. Furthermore, addition of 5-HT to the flow cell mixture also produced a voltammogram with a very different shape (1 μM 5-HT, 80 μM histamine and −0.5 pH units) suggesting that 5-HT was unlikely to have contributed to the analytes measured in the telencephalon (Figure 6H).

Bottom Line: In this study we have used in vitro FSCV to measure the release of analytes in the adult zebrafish telencephalon.We compare different stimulation methods and present a characterization of neurochemical changes in the wild-type zebrafish brain.This study represents the first FSCV recordings in zebrafish, thus paving the way for neurochemical analysis of the fish brain.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroscience, Psychology and Behaviour, University of Leicester Leicester, UK.

ABSTRACT
The zebrafish is an ideal model organism for behavioral genetics and neuroscience. The high conservation of genes and neurotransmitter pathways between zebrafish and other vertebrates permits the translation of research between species. Zebrafish behavior can be studied at both larval and adult stages and recent research has begun to establish zebrafish models for human disease. Fast scan cyclic voltammetry (FSCV) is an electrochemical technique that permits the detection of neurotransmitter release and reuptake. In this study we have used in vitro FSCV to measure the release of analytes in the adult zebrafish telencephalon. We compare different stimulation methods and present a characterization of neurochemical changes in the wild-type zebrafish brain. This study represents the first FSCV recordings in zebrafish, thus paving the way for neurochemical analysis of the fish brain.

No MeSH data available.


Related in: MedlinePlus