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Intrinsic properties of larval zebrafish neurons in ethanol.

Ikeda H, Delargy AH, Yokogawa T, Urban JM, Burgess HA, Ono F - PLoS ONE (2013)

Bottom Line: The behavioral effects of ethanol have been studied in multiple animal models including zebrafish.The intracellular [Ca(2+)] response in MiD3 neurons decreased in 100 mM ethanol, while Mauthner neurons and vestibulospinal neurons required >300 mM ethanol to elicit similar effects.The ethanol effect in Mauthner neurons was reversible following removal of ethanol.

View Article: PubMed Central - PubMed

Affiliation: Section on Model Synaptic Systems, Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland, United States of America.

ABSTRACT
The behavioral effects of ethanol have been studied in multiple animal models including zebrafish. Locomotion of zebrafish larvae is resistant to high concentrations of ethanol in bath solution. This resistance has been attributed to a lower systemic concentration of ethanol in zebrafish when compared with bath solution, although the mechanism to maintain such a steep gradient is unclear. Here we examined whether the intrinsic properties of neurons play roles in this resistance. In order to minimize the contribution of metabolism and diffusional barriers, larvae were hemisected and the anterior half immersed in a range of ethanol concentrations thereby ensuring the free access of bath ethanol to the brain. The response to vibrational stimuli of three types of reticulospinal neurons: Mauthner neurons, vestibulospinal neurons, and MiD3 neurons were examined using an intracellular calcium indicator. The intracellular [Ca(2+)] response in MiD3 neurons decreased in 100 mM ethanol, while Mauthner neurons and vestibulospinal neurons required >300 mM ethanol to elicit similar effects. The ethanol effect in Mauthner neurons was reversible following removal of ethanol. Interestingly, activities of MiD3 neurons displayed spontaneous recovery in 300 mM ethanol, suggestive of acute tolerance. Finally, we examined with mechanical vibration the startle response of free-swimming larvae in 300 mM ethanol. Ethanol treatment abolished long latency startle responses, suggesting a functional change in neural processing. These data support the hypothesis that individual neurons in larval zebrafish brains have distinct patterns of response to ethanol dictated by specific molecular targets.

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Activity of reticulospinal neurons in ethanol.Fluorescence intensity of Mauthner neurons (A–C), vestibulospinal neurons (D, F) and MiD3 neurons (E, F). Sound/vibration stimuli were applied to sectioned (A, D, E) or intact larvae (B) bathed in 0, 30, 100, 300 and 1000 mM ethanol. The black, blue, green, orange and red lines correspond to 0, 30, 100, 300, and 1000 mM ethanol, respectively. The peak of ΔF/F normalized to values at 0 mM was plotted against the EtOH concentration in C and F. (*P<0.05, **P<0.005, ***P<0.001 versus 0 mM ethanol). Six Mauthner neurons, eight vestibulospinal neurons, and five MiD3 neurons were measured. Stimuli were applied and calcium transients were elicited at each concentration 2–5 times. The numbers of samplings are shown in parentheses.
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pone-0063318-g003: Activity of reticulospinal neurons in ethanol.Fluorescence intensity of Mauthner neurons (A–C), vestibulospinal neurons (D, F) and MiD3 neurons (E, F). Sound/vibration stimuli were applied to sectioned (A, D, E) or intact larvae (B) bathed in 0, 30, 100, 300 and 1000 mM ethanol. The black, blue, green, orange and red lines correspond to 0, 30, 100, 300, and 1000 mM ethanol, respectively. The peak of ΔF/F normalized to values at 0 mM was plotted against the EtOH concentration in C and F. (*P<0.05, **P<0.005, ***P<0.001 versus 0 mM ethanol). Six Mauthner neurons, eight vestibulospinal neurons, and five MiD3 neurons were measured. Stimuli were applied and calcium transients were elicited at each concentration 2–5 times. The numbers of samplings are shown in parentheses.

Mentions: We bathed the sectioned cranial half of larvae in bath solution containing varying concentrations of ethanol (0, 30, 100, 300 and 1000 mM) and measured activities in 3 types of reticulospinal neurons, i.e. Mauthner neurons, vestibulospinal neurons and MiD3 neurons. Mauthner neuron [Ca2+]i transients were not significantly altered in 30 and 100 mM ethanol, decreased in 300 mM ethanol, and were eliminated in 1 M ethanol (Fig. 3A, C). In vestibulospinal neurons, the overall effect was similar to that of Mauthner neurons (Fig. 3D, F). MiD3 neurons were more sensitive to ethanol compared to the other two neuronal types, showing a marked decrease at 100 mM ethanol resulting in a leftward shift of the dose response curve (Fig. 3E, F).


Intrinsic properties of larval zebrafish neurons in ethanol.

Ikeda H, Delargy AH, Yokogawa T, Urban JM, Burgess HA, Ono F - PLoS ONE (2013)

Activity of reticulospinal neurons in ethanol.Fluorescence intensity of Mauthner neurons (A–C), vestibulospinal neurons (D, F) and MiD3 neurons (E, F). Sound/vibration stimuli were applied to sectioned (A, D, E) or intact larvae (B) bathed in 0, 30, 100, 300 and 1000 mM ethanol. The black, blue, green, orange and red lines correspond to 0, 30, 100, 300, and 1000 mM ethanol, respectively. The peak of ΔF/F normalized to values at 0 mM was plotted against the EtOH concentration in C and F. (*P<0.05, **P<0.005, ***P<0.001 versus 0 mM ethanol). Six Mauthner neurons, eight vestibulospinal neurons, and five MiD3 neurons were measured. Stimuli were applied and calcium transients were elicited at each concentration 2–5 times. The numbers of samplings are shown in parentheses.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3643919&req=5

pone-0063318-g003: Activity of reticulospinal neurons in ethanol.Fluorescence intensity of Mauthner neurons (A–C), vestibulospinal neurons (D, F) and MiD3 neurons (E, F). Sound/vibration stimuli were applied to sectioned (A, D, E) or intact larvae (B) bathed in 0, 30, 100, 300 and 1000 mM ethanol. The black, blue, green, orange and red lines correspond to 0, 30, 100, 300, and 1000 mM ethanol, respectively. The peak of ΔF/F normalized to values at 0 mM was plotted against the EtOH concentration in C and F. (*P<0.05, **P<0.005, ***P<0.001 versus 0 mM ethanol). Six Mauthner neurons, eight vestibulospinal neurons, and five MiD3 neurons were measured. Stimuli were applied and calcium transients were elicited at each concentration 2–5 times. The numbers of samplings are shown in parentheses.
Mentions: We bathed the sectioned cranial half of larvae in bath solution containing varying concentrations of ethanol (0, 30, 100, 300 and 1000 mM) and measured activities in 3 types of reticulospinal neurons, i.e. Mauthner neurons, vestibulospinal neurons and MiD3 neurons. Mauthner neuron [Ca2+]i transients were not significantly altered in 30 and 100 mM ethanol, decreased in 300 mM ethanol, and were eliminated in 1 M ethanol (Fig. 3A, C). In vestibulospinal neurons, the overall effect was similar to that of Mauthner neurons (Fig. 3D, F). MiD3 neurons were more sensitive to ethanol compared to the other two neuronal types, showing a marked decrease at 100 mM ethanol resulting in a leftward shift of the dose response curve (Fig. 3E, F).

Bottom Line: The behavioral effects of ethanol have been studied in multiple animal models including zebrafish.The intracellular [Ca(2+)] response in MiD3 neurons decreased in 100 mM ethanol, while Mauthner neurons and vestibulospinal neurons required >300 mM ethanol to elicit similar effects.The ethanol effect in Mauthner neurons was reversible following removal of ethanol.

View Article: PubMed Central - PubMed

Affiliation: Section on Model Synaptic Systems, Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland, United States of America.

ABSTRACT
The behavioral effects of ethanol have been studied in multiple animal models including zebrafish. Locomotion of zebrafish larvae is resistant to high concentrations of ethanol in bath solution. This resistance has been attributed to a lower systemic concentration of ethanol in zebrafish when compared with bath solution, although the mechanism to maintain such a steep gradient is unclear. Here we examined whether the intrinsic properties of neurons play roles in this resistance. In order to minimize the contribution of metabolism and diffusional barriers, larvae were hemisected and the anterior half immersed in a range of ethanol concentrations thereby ensuring the free access of bath ethanol to the brain. The response to vibrational stimuli of three types of reticulospinal neurons: Mauthner neurons, vestibulospinal neurons, and MiD3 neurons were examined using an intracellular calcium indicator. The intracellular [Ca(2+)] response in MiD3 neurons decreased in 100 mM ethanol, while Mauthner neurons and vestibulospinal neurons required >300 mM ethanol to elicit similar effects. The ethanol effect in Mauthner neurons was reversible following removal of ethanol. Interestingly, activities of MiD3 neurons displayed spontaneous recovery in 300 mM ethanol, suggestive of acute tolerance. Finally, we examined with mechanical vibration the startle response of free-swimming larvae in 300 mM ethanol. Ethanol treatment abolished long latency startle responses, suggesting a functional change in neural processing. These data support the hypothesis that individual neurons in larval zebrafish brains have distinct patterns of response to ethanol dictated by specific molecular targets.

Show MeSH
Related in: MedlinePlus