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Thörnqvist, Per-Ove
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Publications (10 of 21) Show all publications
Koeck, B., Zavorka, L., Aldven, D., Naslund, J., Arlinghaus, R., Thörnqvist, P.-O., . . . Johnsson, J. I. (2019). Angling selects against active and stress-resilient phenotypes in rainbow trout. Canadian Journal of Fisheries and Aquatic Sciences, 76(2), 320-333
Open this publication in new window or tab >>Angling selects against active and stress-resilient phenotypes in rainbow trout
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2019 (English)In: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533, Vol. 76, no 2, p. 320-333Article in journal (Refereed) Published
Abstract [en]

Selection induced by human harvest can lead to different patterns of phenotypic change than selection induced by natural predation and could be a major driving force of evolution of wild populations. The vulnerability of individuals to angling depends on the individual decision to ingest the bait, possibly mediated by their neuroendocrine response towards the associated stimulus. To investigate the mechanisms behind individual vulnerability to angling, we conducted angling experiments in replicated ponds and quantified individual behavioral traits and neuroendocrine stress responsiveness in two salmonid species, rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta). We discovered a phenotypic syndrome in rainbow trout, but not in brown trout, where lower serotonergic and dopaminergic brain activity and cortisol levels (i.e., lower stress responsiveness) in response to a standardized experimental stressor were associated with higher activity, forming a proactive phenotype that showed increased vulnerability to angling. Our results show that angling targets the most stress-resilient and active phenotypes of rainbow trout, supporting the suggestion that fishing-induced phenotypic selection may lead to an increased representation of stress-responsive and low-activity phenotypes in harvested populations.

National Category
Fish and Aquacultural Science Zoology
Identifiers
urn:nbn:se:uu:diva-377332 (URN)10.1139/cjfas-2018-0085 (DOI)000456966600011 ()
Funder
Swedish Research Council Formas
Available from: 2019-02-25 Created: 2019-02-25 Last updated: 2019-02-25Bibliographically approved
Thörnqvist, P.-O., McCarrick, S., Ericsson, M., Roman, E. & Winberg, S. (2019). Bold zebrafish (Danio rerio) express higher levels of delta opioid and dopamine D2 receptors in the brain compared to shy fish. Behavioural Brain Research, 359, 927-934
Open this publication in new window or tab >>Bold zebrafish (Danio rerio) express higher levels of delta opioid and dopamine D2 receptors in the brain compared to shy fish
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2019 (English)In: Behavioural Brain Research, ISSN 0166-4328, E-ISSN 1872-7549, Vol. 359, p. 927-934Article in journal (Refereed) Published
Abstract [en]

Individual variation in coping with environmental challenges is a well-known phenomenon across vertebrates, including teleost fish. Dopamine is the major transmitter in the brain reward networks, and important for motivational processes and stress coping. Functions of the endogenous opioid system are not well studied in teleosts. However, in mammals the activity in the brain reward networks is regulated by the endogenous opioid system. This study aimed at investigating if there was a correlation between risk-taking behavior and the expression of dopamine and opioid receptors in the zebrafish (Danio rerio) brain. Risk-taking behavior was assessed in a novel tank diving test, and the most extreme high risk taking, i.e. bold, and low risk taking, i.e. shy, fish were sampled for qPCR analysis of whole brain gene expression. The expression analysis showed a significantly higher expression of the dopamine D2 receptors (drd2a and drd2b) and the delta opioid receptor (DOR; oprd1b) in bold compared to shy fish. Besides reward and reinforcing properties, DORs are also involved in emotional responses. Dopamine D2 receptors are believed to be important for active stress coping in rodents, and taken together the results of the current study suggest similar functions in zebrafish. However, additional experiments are required to clarify how dopamine and opioid receptor activation affect behavior and stress coping in this species.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Animal personality, Behavior, Boldness, Dopamine receptor, Opioid receptor, Risk taking, Shyness
National Category
Neurosciences
Identifiers
urn:nbn:se:uu:diva-376722 (URN)10.1016/j.bbr.2018.06.017 (DOI)000456222600107 ()29935279 (PubMedID)
Funder
Swedish Research Council
Available from: 2019-02-11 Created: 2019-02-11 Last updated: 2019-02-11Bibliographically approved
Mustafa, A., Thörnqvist, P.-O., Roman, E. & Winberg, S. (2019). The aggressive spiegeldanio, carrying a mutation in the fgfr1a gene, has no advantage in dyadic fights with zebrafish of the AB strain. Behavioural Brain Research, 370, Article ID 111942.
Open this publication in new window or tab >>The aggressive spiegeldanio, carrying a mutation in the fgfr1a gene, has no advantage in dyadic fights with zebrafish of the AB strain
2019 (English)In: Behavioural Brain Research, ISSN 0166-4328, E-ISSN 1872-7549, Vol. 370, article id 111942Article in journal (Refereed) Published
Abstract [en]

Zebrafish which carries a mutation in the fibroblast growth factor receptor 1A (fgfr1a), also known as spiegeldanio (spd), has previously been reported to be bolder and more aggressive than wildtype (AB) zebrafish. However, in previous studies aggression has been quantified in mirror tests. In dyadic fights the behavior of the combatants is modified by the behavior of their opponent, and fighting a mirror has been reported to have different effects on brain gene expression and brain monoaminergic systems. In the present study aggression was quantified in fgfr1a mutants and AB zebrafish using a mirror test after which the fish were allowed to interact in pairs, either consisting of two fgfr1a mutants or one AB and one fgfr1a mutant fish. Following dyadic interaction aggressive behavior was again quantified in individual fish in a second mirror test after which the fish were sacrificed and brain tissue analyzed for monoamines and monoamine metabolites. The results confirm that fgfr1a mutants are more aggressive than AB zebrafish in mirror tests. However, fgfr1a mutant fish did not have any advantage in fights for social dominance, and agonistic behavior of fgfr1a mutants did not differ from that of AB fish during dyadic interactions. Moreover, as the AB fish, fgfr1a mutant fish losing dyadic interactions showed a typical loser effect and social subordination resulted in an activation of the brain serotonergic system in fgfr1a mutants as well as in AB fish. Overall the effects of dyadic interaction were similar in fgfr1a mutant fish and zebrafish of the AB strain.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2019
Keywords
Aggression, Agonistic behavior, Dominance, Dopamine, Scrotonin
National Category
Developmental Biology Medical Genetics
Identifiers
urn:nbn:se:uu:diva-390372 (URN)10.1016/j.bbr.2019.111942 (DOI)000474323900003 ()31085203 (PubMedID)
Funder
Swedish Research Council
Available from: 2019-08-12 Created: 2019-08-12 Last updated: 2019-08-12Bibliographically approved
Roman, E., Brunberg, R., Mustafa, A., Thörnqvist, P.-O. & Winberg, S. (2018). Behavioral profiling using a modified version of the zebrafish multivariate concentric square field™ (zMCSF) test. In: Grant R, Allen T, Spink A, Sullivan M (Ed.), Measuring Behavior 2018: 11th International Conference on Methods and Techniques in Behavioral Research. Paper presented at Measuring Behavior, Manchester, 5-8 June, 2018. (pp. 27-29).
Open this publication in new window or tab >>Behavioral profiling using a modified version of the zebrafish multivariate concentric square field™ (zMCSF) test
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2018 (English)In: Measuring Behavior 2018: 11th International Conference on Methods and Techniques in Behavioral Research / [ed] Grant R, Allen T, Spink A, Sullivan M, 2018, p. 27-29Conference paper, Published paper (Refereed)
Keywords
behavioral profiling, zMCSF, multivariate concentric square field, zebrafish
National Category
Neurosciences
Identifiers
urn:nbn:se:uu:diva-356583 (URN)978-1-910029-39-8 (ISBN)
Conference
Measuring Behavior, Manchester, 5-8 June, 2018.
Available from: 2018-08-01 Created: 2018-08-01 Last updated: 2018-08-01Bibliographically approved
Abreu, M. S., Messias, J. P. M., Thörnqvist, P.-O., Winberg, S. & Soares, M. C. (2018). Monoaminergic levels at the forebrain and diencephalon signal for the occurrence of mutualistic and conspecific engagement in client reef fish. Scientific Reports, 8, Article ID 7346.
Open this publication in new window or tab >>Monoaminergic levels at the forebrain and diencephalon signal for the occurrence of mutualistic and conspecific engagement in client reef fish
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2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 7346Article in journal (Refereed) Published
Abstract [en]

Social interactions are commonly found among fish as in mammals and birds. While most animals interact socially with conspecifics some however are also frequently and repeatedly observed to interact with other species (i.e. mutualistic interactions). This is the case of the (so-called) fish clients that seek to be cleaned by other fish (the cleaners). Clients face an interesting challenge: they raise enough motivation to suspend their daily activities as to selectively visit and engage in interactions with cleaners. Here we aimed, for the first time, to investigate the region-specific brain monoaminergic level differences arising from individual client fish when facing a cleaner (interspecific context) compared to those introduced to another conspecific (socio-conspecific context). We show that monoaminergic activity differences occurring at two main brain regions, the diencephalon and the forebrain, are associated with fish clients' social and mutualistic activities. Our results are the first demonstration that monoaminergic mechanisms underlie client fish mutualistic engagement with cleanerfish. These pathways should function as a pre-requisite for cleaning to occur, providing to clients the cognitive and physiological tools to seek to be cleaned.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2018
National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-358095 (URN)10.1038/s41598-018-25513-6 (DOI)000431737300032 ()29743658 (PubMedID)
Funder
Swedish Research CouncilSwedish Research Council Formas
Available from: 2018-08-24 Created: 2018-08-24 Last updated: 2018-08-24Bibliographically approved
Mustafa, A., Cetinkaya, D., Cheng, X., Thörnqvist, P.-O. & Winberg, S. (2018). Spiegeldanio: A bold and aggressive fish but what if it loses a fight?. In: Grant R, Allen T, Spink A, Sullivan M (Ed.), Measuring Behavior 2018: Conference Proceedings. Paper presented at Measuring Behavior 2018: 11th International Conference on Methods and Techniques in Behavioral Research, 5-8 June 2018, Manchester Metropolitan University, UK (pp. 24-26).
Open this publication in new window or tab >>Spiegeldanio: A bold and aggressive fish but what if it loses a fight?
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2018 (English)In: Measuring Behavior 2018: Conference Proceedings / [ed] Grant R, Allen T, Spink A, Sullivan M, 2018, p. 24-26Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Introduction

Aggression is a competition based survival strategy. The spiegeldanio (spd) strain of zebrafish (Danio rerio), which has a mutation in the fibroblast growth factor receptor 1a, is bolder and more aggressive than the wild type fish [1]. Usually a socially dominant fish has preferential access to food, mate and shelter, and shows very characteristic postures like erection of the fins. It is also aggressive frequently biting, striking and chasing the subordinate fish as well as threatening its own mirror image in mirror tests [2]. However, what happens when an already known bold and dominant fish like spiegeldanio loses a dyadic fight. Spd fish are more aggressive in mirror tests, attacking their mirror image more frequently than wild type conspecifics. However, are they more aggressive in dyadic fights? Do they show an inhibition of aggressive behaviour when losing fights, the typical loser effect? The behavioural inhibition observed in animals losing fights for dominance is at least in part believed to be mediated by an activation of the brain serotonin (5-hydroxytryptamine, 5-HT) system. Do spd fish show a typical increase in brain 5-HT activity in response to social subordination? Dopamine (DA), on the other hand, is associated with aggression and social dominance. What are the effects of winning and losing fights for social dominance in spd fish? In the present study these questions were addressed in an attempt to increase or understanding of the control of agonistic behaviour and social stress.

Animals and Methods

The Spd strain of zebrafish were raised and reared at 27°C in an Aquaneering Zebrafish system at Uppsala University Biomedical Center. The animals were kept at a 14:10 h of light-dark photoperiod. The water used in the fish tanks was Uppsala municipal tap water (pH 7.2-7.6) of which 10% was exchanged daily. Fish were fed twice daily with Tropical energy food (Aquatic Nature, Belgium) and Artemia (Platinum Grade 0, Argentemia, Argent, Aquaculture, Redmond, USA). The use of animals was approved by the Uppsala Animal Ethical Committee (permit Dnr 55/13) and followed the guidelines of the Swedish Legislation on Animal Experimentation (Animal Welfare Act SFS1998:56), and the European Union Directive on the Protection of Animals Used for Scientific Purposes (Directive 2010/63/EU). The fish were transferred to the individual compartments of dimension 29 x 7.5 x 20 cm (length x breadth x height) in experimental tanks used for dyadic interaction and allowed to recover in isolation overnight. These experimental tanks were made from poly methyl methacrylate plastic and each tank was equipped with a submerged pump with filter (Eheim, typ 2006020, pumping capacity 1/h180, made in China), a heater (Sera aquarium, 25W, made in EU) and an air stone, all of which were placed at the back of the tank separated from the fish by a white perforated PVC screen (Figure 1). The setup of the arena was such that the two fish (1 dyadic pair) had an olfactory but not any visual cue of each other before the dyadic interaction. In the mirror test the fish were made to fight against the mirror image that was displayed in the mirror which was pasted on the wall of the arena. Prior to the beginning of the dyadic contest the mirror was covered with a black plexiglas slide cover. The experiment was carried out in the following sequence: The fishes were netted out and placed in the arena in the compartments A and B (Figure 1) and separated from each other by a partition. The cover of the mirror (opaque black PVC partition, Figure 1) was then removed and fish were made to interact with their own mirror image for 10 minutes. Then the slide covering the mirror was pulled down and the middle separating partition was pulled out and the fish were given an opportunity to fight. Dyadic fight was recorded two times, morning and evening on day one with the help of a video filming camera. Then next day in the morning the dyadic fight was again recorded. During the dyadic interaction the two fishes indulged in mutual display of aggressive behaviour which was followed by chasing and biting attacks performed by the dominant fish over the subordinate fish. Then middle partition was introduced again. Fish were given 6 minutes to habituate and the cover from the mirror was removed and fishes were again allowed to interact with their mirror image. Again the mirror was covered and the fish was allowed to get involved in the dyadic fight.  Then each fish was taken out from the compartment at the same time and sacrificed for sampling of brain tissue.

The three dimensional model of tank used in the behavioural tests I) Tank used for mirror test and for dyadic fight later on. It consists of two compartments, A and B. The movable partition separating the two compartments would be removed during the dyadic fight test. Compartment C is located at the back and is separated from the compartment A and B with the help of white coloured opaque perforated partition. It contains an air stone (for diffusion of air bubbles), heater (27°C), water pump (for circulation of water) and a drainage tube to exchange the water. II) Diagram of the settings used for dyadic interactions. The mirrors are covered with the help of a black PVC slide and the middle partition is pulled out. This allows the fish to interact.

Brain dissection and analysis of monaoamines and monoamine metabolites

Brains were divided into forebrain (telencephalon and diencephalon), optic tectum and the rest (here denoted brain stem). The frozen brains were homogenised in 4% (w/v) ice-cold perchloric acid containing 100 ng/ml 3, 4-dihydroxybenzylamine (DHBA, the internal standard) using a Sonifier cell disruptor B-30 (Branson Ultrasonics, Danbury, CT, USA) and were immediately put on dry ice. Subsequently, the homogenised samples were thawed and centrifuged at 15,000 rpm for 10 min at 4o C. The supernatant was used for high performance liquid chromatography with electrochemical detection (HPLC-EC), analysing the monoamines dopamine (DA) and serotonin (5-hydroxytryptamine, 5-HT) as well as the DA metabolite 3, 4-dihydroxyphenylacetic acid (DOPAC) and the 5-HT metabolite 5-hydroxyindoleacetic acid (5-HIAA), as described by Øverli et al. [3]. In short, the HPLC-EC system consisted of a solvent delivery system model 582 (ESA, Bedford, MA, USA), an autoinjector Midas type 830 (Spark Holland, Emmen, the Netherlands), a reverse phase column (Reprosil-Pur C18-AQ 3 µm, 100 mm × 4 mm column, Dr. Maisch HPLC GmbH, Ammerbuch-Entringen, Germany) kept at 40° C and an ESA 5200 Coulochem II EC detector (ESA, Bedford, MA, USA) with two electrodes at reducing and oxidizing potentials of -40 mV and +320 mV. A guarding electrode with a potential of +450 mV was employed before the analytical electrodes to oxidize any contaminants. The mobile phase consisted of 75 mM sodium phosphate, 1.4 mM sodium octyl sulphate and 10 µM EDTA in deionised water containing 7 % acetonitrile brought to pH 3.1 with phosphoric acid. The quantification of samples was done by comparing it with standard solutions of known concentrations. DHBA was used as an internal standard to correct for recovery with the help of HPLC software ClarityTM (Data Apex Ltd, Czech Republic). The serotonergic and dopaminergic activity was measured as the ratio of 5-HIAA/5-HT and DOPAC/DA respectively. The brain monoamines were normalized with respect to brain protein weights which were determined with Bicinchoninic acid protein determination kit (Sigma Aldrich, Sweden). The assay was read at a wavelength of 570 nm with the help of a plate reader (Labsystems multiskan 352, Labsystems Thermo Fisher Scientific).

Results

A clear dominant subordinate hierarchy was established within 30 minutes of dyadic interaction. The number of aggressive acts (bites, strikes and chases) performed by the looser fish decreased significantly from the first dyadic fight to the last (i.e. the fourth) dyadic fight. For the winner fish the number of aggressive acts performed against a mirror during the second mirror test increased or remained same as before after winning a dyadic fight, whereas for the looser fish it decreased significantly. The results from the present study indicate that subordinate fish have higher 5-HIAA/5-HT ratio in the optic tectum as compared to the dominants. More results from this study would be presented at the conference.

References

1. Norton W, Bally-Cuif L (2010) Adult zebrafish as a model organism for behavioural genetics. BMC Neurosci. 11:90.

2. Rowland WJ (1999) Studying visual cues in fish behaviour: a review of ethological techniques. Env Biol Fishes. 56:285-305.

3. Øverli Ø, Harris CA, Winberg S (1999) Short-term effects of fights for social dominance and the establishment of dominant-subordinate relationships on brain monoamines and cortisol in rainbow trout. Brain Behav Evol. 54:263-275.

 

 

National Category
Neurosciences
Identifiers
urn:nbn:se:uu:diva-361560 (URN)978-1-910029-39-8 (ISBN)
Conference
Measuring Behavior 2018: 11th International Conference on Methods and Techniques in Behavioral Research, 5-8 June 2018, Manchester Metropolitan University, UK
Available from: 2018-09-25 Created: 2018-09-25 Last updated: 2018-09-25Bibliographically approved
Rosengren, M., Thörnqvist, P.-O., Winberg, S. & Sundell, K. (2018). The brain-gut axis of fish: Rainbow trout with low and high cortisol response show innate differences in intestinal integrity and brain gene expression. Paper presented at 8th International Symposium on Fish Endocrinology, JUN 28-JUL 02, 2016, Gothenburg, SWEDEN. General and Comparative Endocrinology, 257, 235-245
Open this publication in new window or tab >>The brain-gut axis of fish: Rainbow trout with low and high cortisol response show innate differences in intestinal integrity and brain gene expression
2018 (English)In: General and Comparative Endocrinology, ISSN 0016-6480, E-ISSN 1095-6840, Vol. 257, p. 235-245Article in journal (Refereed) Published
Abstract [en]

In fish, the stress hormone cortisol is released through the action of the hypothalamic pituitary interrenal axis (HPI-axis). The reactivity of this axis differs between individuals and previous studies have linked this to different behavioural characteristics and stress coping styles. In the current study, low and high responding (LR and HR) rainbow trout in terms of cortisol release during stress were identified, using a repeated confinements stress test. The expression of stress related genes in the forebrain and the integrity of the stress sensitive primary barrier of the intestine was examined. The HR trout displayed higher expression levels of mineralocorticoid and serotonergic receptors and serotonergic re-uptake pumps in the telencephalon during both basal and stressed conditions. This confirms that HPI-axis reactivity is linked also to other neuronal behavioural modulators, as both the serotonergic and the corticoid system in the telencephalon are involved in behavioural reactivity and cognitive processes. Involvement of the HPI-axis in the brain-gut-axis was also found. LR trout displayed a lower integrity in the primary barrier of the intestine during basal conditions compared to the HR trout. However, following stress exposure, LR trout showed an unexpected increase in intestinal integrity whereas the HR trout instead suffered a reduction. This could make the LR individuals more susceptible to pathogens during basal conditions where instead HR individuals would be more vulnerable during stressed conditions. We hypothesize that these barrier differences are caused by regulation/effects on tight junction proteins possibly controlled by secondary effects of cortisol on the intestinal immune barrier or differences in parasympathetic reactivity.

Place, publisher, year, edition, pages
ACADEMIC PRESS INC ELSEVIER SCIENCE, 2018
Keywords
Corticoid receptors, HPI-axis reactivity, Intestinal barrier function, Stress coping styles, Serotonin, Telencephalon
National Category
Zoology
Identifiers
urn:nbn:se:uu:diva-348392 (URN)10.1016/j.ygcen.2017.09.020 (DOI)000424858400026 ()28947388 (PubMedID)
Conference
8th International Symposium on Fish Endocrinology, JUN 28-JUL 02, 2016, Gothenburg, SWEDEN
Funder
Helge Ax:son Johnsons stiftelse Swedish Research Council Formas, 229- 2009-1495, 223-2011-1073
Available from: 2018-04-16 Created: 2018-04-16 Last updated: 2018-04-16Bibliographically approved
de Abreu, M. S., Messias, J. P. M., Thörnqvist, P.-O., Winberg, S. & Soares, M. C. (2018). The variable monoaminergic outcomes of cleaner fish brains when facing different social and mutualistic contexts. PeerJ, 6, Article ID e4830.
Open this publication in new window or tab >>The variable monoaminergic outcomes of cleaner fish brains when facing different social and mutualistic contexts
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2018 (English)In: PeerJ, ISSN 2167-8359, E-ISSN 2167-8359, Vol. 6, article id e4830Article in journal (Refereed) Published
Abstract [en]

The monoamines serotonin and dopamine are important neuromodulators present in the central nervous system, known to be active regulators of social behaviour in fish as in other vertebrates. Our aim was to investigate the region-specific brain monoaminergic differences arising when individual cleaners face a client (mutualistic context) compared to when they are introduced to another conspecific (conspecific context), and to understand the relevance of visual assessment compared to the impact of physical contact with any partner. We demonstrated that serotoninergic activity at the diencephalon responds mostly to the absence of physical contact with clients whereas cerebellar dopaminergic activity responds to actual cleaning engagement. We provide first insights on the brain's monoaminergic (region-specific) response variations, involved in the expression of cleaner fishes' mutualistic and conspecific behaviour. These results contribute to a better understanding of the monoaminergic activity in accordance to different socio-behavioural contexts.

Place, publisher, year, edition, pages
PEERJ INC, 2018
Keywords
Serotonin, Dopamine, Cleanerfish, Mutualisms, Physical contact
National Category
Behavioral Sciences Biology
Identifiers
urn:nbn:se:uu:diva-357741 (URN)10.7717/peerj.4830 (DOI)000434231500005 ()29844980 (PubMedID)
Funder
Swedish Research CouncilSwedish Research Council Formas
Available from: 2018-08-30 Created: 2018-08-30 Last updated: 2018-08-30Bibliographically approved
Cocco, A., Rönnberg, A. M., Jin, Z., André, G. I., Vossen, L. E., Bhandage, A. K., . . . Winberg, S. (2017). Characterization of the gamma-aminobutyric acid signaling system in the zebrafish (danio rerio hamilton) central nervous system by reverse transcription-quantitative polymerase chain reaction. Neuroscience, 343, 300-321
Open this publication in new window or tab >>Characterization of the gamma-aminobutyric acid signaling system in the zebrafish (danio rerio hamilton) central nervous system by reverse transcription-quantitative polymerase chain reaction
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2017 (English)In: Neuroscience, ISSN 0306-4522, E-ISSN 1873-7544, Vol. 343, p. 300-321Article in journal (Refereed) Published
Abstract [en]

In the vertebrate brain, inhibition is largely mediated by raminobutyric acid (GABA). This neurotransmitter comprises a signaling machinery of GABA(A), GABA(B) receptors, transporters, glutamate decarboxylases (gads) and 4-aminobutyrate aminotransferase (abat), and associated proteins. Chloride is intimately related to GABAA receptor conductance, GABA uptake, and GADs activity. The response of target neurons to GABA stimuli is shaped by chloride-cation co-transporters (CCCs), which strictly control Cl- gradient across plasma membranes. This research profiled the expression of forty genes involved in GABA signaling in the zebrafish (Danio rerio) brain, grouped brain regions and retinas. Primer pairs were developed for reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The mRNA levels of the zebrafish GABA system share similarities with that of mammals, and confirm previous studies in non-mammalian species. Proposed GABAA receptors are alpha(1)beta(2)gamma(2), alpha(1)beta(2)delta, alpha(2b)beta(3), alpha(2b)beta(3)delta, alpha(4)beta(2)gamma(2), alpha(4)beta(2)gamma, alpha(6b)beta(2)gamma(2) and alpha(6b)beta(2)delta. Regional brain differences were documented. Retinal hetero- or homomeric rho-composed GABAA receptors could exist, accompanying alpha(1)beta(y)gamma(2), alpha(1)beta(y)delta, alpha(6a)beta(y)gamma(2,) alpha(6a)beta(y)delta. Expression patterns of alpha(6a) and alpha(6b) were opposite, with the former being more abundant in retinas, the latter in brains. Given the stoichiometry alpha(6w)beta(y)gamma(z), alpha(6a-) or alpha(6b)-containing receptors likely have different regulatory mechanisms. Different gene isoforms could originate after the rounds of genome duplication during teleost evolution. This research depicts that one isoform is generally more abundantly expressed than the other. Such observations also apply to GABAB receptors, GABA transporters, GABA-related enzymes, CCCs and GABAA receptor associated proteins, whose presence further strengthens the proof of a GABA system in zebrafish.

Keywords
GABA, comparative neuroscience, teleost, zebrafish, neurotransmitter systems, receptors
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-317583 (URN)10.1016/j.neuroscience.2016.07.018 (DOI)000393269100030 ()27453477 (PubMedID)
Funder
Swedish Research Council
Available from: 2017-03-24 Created: 2017-03-24 Last updated: 2018-04-17Bibliographically approved
Ullah, I., Zuberi, A., Khan, K. U., Ahmad, S., Thörnqvist, P.-O. & Winberg, S. (2017). Effects of enrichment on the development of behaviour in an endangered fish mahseer (Tor putitora). Applied Animal Behaviour Science, 186, 93-100
Open this publication in new window or tab >>Effects of enrichment on the development of behaviour in an endangered fish mahseer (Tor putitora)
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2017 (English)In: Applied Animal Behaviour Science, ISSN 0168-1591, E-ISSN 1872-9045, Vol. 186, p. 93-100Article in journal (Refereed) Published
Abstract [en]

Structural enrichment in the rearing environment, not only promotes fish welfare, but also affects several aspects of behavioural biology of fish in aquaculture. Here an attempt was made to use physical enrichment to improve the behaviour of hatchery-reared fish. In this study, three groups of 15 days old mahseer (Tor putitora) hatchlings were reared up to advanced fry stage in barren (without any substrate), physically-enriched (gravel bed, substrate and plants) and semi-natural environments (earthen pond having a natural feed) respectively and the behavioural profiles of fish from these environments were compared. We illustrate that increased structural complexity during early life significantly affect various behavioural characteristics of the fish. Exploratory behaviour, predation and anti-predatory response were significantly (p < 0.05) higher in fish reared in physical enrichment and semi-natural environment than in barren-reared fish. These results have important implications for a possible way of improving the outcomes of restocking program of endangered fish species by modifying conventional hatchery-rearing environments.

Keywords
Early rearing, Enrichment, Semi-natural environment, Behavioural responses
National Category
Fish and Aquacultural Science Zoology
Identifiers
urn:nbn:se:uu:diva-316416 (URN)10.1016/j.applanim.2016.10.016 (DOI)000392770600014 ()
Available from: 2017-03-02 Created: 2017-03-02 Last updated: 2017-11-29Bibliographically approved
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