The Histamine System in Zebrafish Brain: Organization, Receptors, and Behavioral Roles.

Three of the four histamine receptors have been identified in zebrafish. Whereas only one histamine receptor 1 gene (hrh1) is known, two copies of histamine receptor 2 (hrh2a and hrh2b) have been identified. Although initially only one gene encoding for histamine receptor 3 (hrh3) was recognized in zebrafish, the genome database contains information for two more hrh3-like genes, whereas no genes corresponding for histamine receptor 4 with expression mainly in the immune system have been identified.

The bullies are the leaders of the next generation: Inherited aminergic neurotransmitter system changes in socially dominant zebrafish, Danio rerio.

We studied the social hierarchy in zebrafish and assessed differences in neurotransmitters and behavior in the F1 generation offspring of dominant and subordinate zebrafish (Danio rerio). We used behavioral assays to study locomotion, ability to complete cognitive tasks, social interaction and aggression. To study the neurochemical changes, we applied quantitative polymerase chain reaction, high pressure liquid chromatography and immunohistochemistry.

Embryonic exposure to valproic acid affects the histaminergic system and the social behaviour of adult zebrafish (Danio rerio).

Background And Purpose: Histamine modulates several behaviours and physiological functions, and its deficiency is associated with neuropsychiatric disorders. Gestational intake of valproic acid (VPA) is linked to autism spectrum disorder (ASD), characterized by impaired sociability and stereotypies. VPA effects on the neurochemistry and functional morphology of the histaminergic system in ASD are unclear.

Storage of neural histamine and histaminergic neurotransmission is VMAT2 dependent in the zebrafish.

Monoaminergic neurotransmission is greatly dependent on the function of the vesicular monoamine transporter VMAT2, which is responsible for loading monoamines into secretory vesicles. The role of VMAT2 in histaminergic neurotransmission is poorly understood. We studied the structure and function of the histaminergic system in larval zebrafish following inhibition of VMAT2 function by reserpine.

Protective Effects of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Against Oxidative Stress in Zebrafish Hair Cells.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a pleiotropic neuropeptide, with known antiapoptotic functions. Our previous in vitro study has demonstrated the ameliorative role of PACAP-38 in chicken hair cells under oxidative stress conditions, but its effects on living hair cells is now yet known. Therefore, the aim of the present study was to investigate in vivo the protective role of PACAP-38 in hair cells found in zebrafish (Danio rerio) sense organs-neuromasts.

A Novel Developmental Role for Dopaminergic Signaling to Specify Hypothalamic Neurotransmitter Identity.

Hypothalamic neurons expressing histamine and orexin/hypocretin (hcrt) are necessary for normal regulation of wakefulness. In Parkinson's disease, the loss of dopaminergic neurons is associated with elevated histamine levels and disrupted sleep/wake cycles, but the mechanism is not understood. To characterize the role of dopamine in the development of histamine neurons, we inhibited the translation of the two non-allelic forms of tyrosine hydroxylase (th1 and th2) in zebrafish larvae.

Effect of Ionic Liquids on Zebrafish (Danio rerio) Viability, Behavior, and Histology; Correlation between Toxicity and Ionic Liquid Aggregation.

The effect of 11 common amidinium, imidazolium, and phosphonium based ionic liquids (ILs) on zebrafish (Danio rerio) and Chinese hamster ovary cells (CHO) was investigated with specific emphasis on the effect of anion and cation chain length and aggregation of phosphonium based ILs. Viability and behavioral alteration in the locomotor activity and place preference, after IL treatment of 5 days postfertilization larvae, was recorded. Behavior and histological damage evaluation was performed for adult fish in order to get insight into the long-term effects of two potential biomass-dissolving ILs, [DBNH][OAc] and [P4441][OAc].

Effects of acoustic levitation on the development of zebrafish, Danio rerio, embryos.

Acoustic levitation provides potential to characterize and manipulate material such as solid particles and fluid in a wall-less environment. While attempts to levitate small animals have been made, the biological effects of such levitation have been scarcely documented. Here, our goal was to explore if zebrafish embryos can be levitated (peak pressures at the pressure node and anti-node: 135 dB and 144 dB, respectively) with no effects on early development.

Amigo adhesion protein regulates development of neural circuits in zebrafish brain.

The Amigo protein family consists of three transmembrane proteins characterized by six leucine-rich repeat domains and one immunoglobulin-like domain in their extracellular moieties. Previous in vitro studies have suggested a role as homophilic adhesion molecules in brain neurons, but the in vivo functions remain unknown. Here we have cloned all three zebrafish amigos and show that amigo1 is the predominant family member expressed during nervous system development in zebrafish.

Developmental roles of brain histamine.

Histamine appears early during brain development, has been shown to regulate fetal and adult brain-derived stem cells in a receptor type-dependent manner, and has widespread actions on systems involved in arousal and movement. Developmental studies in both rodents and zebrafish have elucidated the spatiotemporal patterning of the histaminergic system and, in zebrafish, have revealed the mechanisms whereby histamine regulates the number of hypocretin/orexin (hcrt) neurons, which in turn may regulate the number of histaminergic cells. Recent demonstrations of increased numbers of histaminergic neurons in patients with narcolepsy highlight the importance, for our understanding of both normal and pathological brain function, of understanding these interactions.

Artificial selection on relative brain size reveals a positive genetic correlation between brain size and proactive personality in the guppy.

Animal personalities range from individuals that are shy, cautious, and easily stressed (a "reactive" personality type) to individuals that are bold, innovative, and quick to learn novel tasks, but also prone to routine formation (a "proactive" personality type). Although personality differences should have important consequences for fitness, their underlying mechanisms remain poorly understood. Here, we investigated how genetic variation in brain size affects personality.

Acute ethanol treatment upregulates Th1, Th2, and Hdc in larval zebrafish in stable networks.

Earlier studies in zebrafish have revealed that acutely given ethanol has a stimulatory effect on locomotion in fish larvae but the mechanism of this effect has not been revealed. We studied the effects of ethanol concentrations between 0.75 and 3.

Presenilin1 regulates histamine neuron development and behavior in zebrafish, danio rerio.

Modulatory neurotransmitters, including the histaminergic system, are essential in mediating cognitive functions affected in Alzheimer's disease (AD). The roles of disease genes associated with AD, most importantly the presenilin1 gene (psen1), are poorly understood. We studied the role of psen1 in plasticity of the brain histaminergic system using a novel psen1 mutant zebrafish, Danio rerio.

Organization of the histaminergic system in adult zebrafish (Danio rerio) brain: neuron number, location, and cotransmitters.

Histamine is an essential factor in the ascending arousal system (AAS) during motivated behaviors. Histamine and hypocretin/orexin (hcrt) are proposed to be responsible for different aspects of arousal and wakefulness, histamine mainly for cognitive and motivated behaviors. In this study we visualized the entire histaminergic neuron population in adult male and female zebrafish brain and quantified the histaminergic neuron numbers.

The histaminergic system regulates wakefulness and orexin/hypocretin neuron development via histamine receptor H1 in zebrafish.

The histaminergic and hypocretin/orexin (hcrt) neurotransmitter systems play crucial roles in alertness/wakefulness in rodents. We elucidated the role of histamine in wakefulness and the interaction of the histamine and hcrt systems in larval zebrafish. Translation inhibition of histidine decarboxylase (hdc) with morpholino oligonucleotides (MOs) led to a behaviorally measurable decline in light-associated activity, which was partially rescued by hdc mRNA injections and mimicked by histamine receptor H1 (Hrh1) antagonist pyrilamine treatment.

Adaptive changes in zebrafish brain in dominant-subordinate behavioral context.

Male zebrafish were held in dyadic social stress situation for a period of 5 days, to characterize stress coping styles and to investigate the role of the underlying neuroendocrine mechanisms in establishing dominant-subordinate relationships. A strong consistent dominant-subordinate relationship was formed in ten out of the sixteen pairs of fish (62.5%).

Conservation, expression, and knockdown of zebrafish plxnb2a and plxnb2b.

In mice lacking Plexin B2, a receptor of the axon guidance molecules Semaphorin 4C and Semaphorin 4D, the closure of the neural tube and structural organization of the cerebellum are severely impaired. We cloned two Plexin B2 orthologs, plxnb2a and plxnb2b, in zebrafish, which is a widely used model for the development of the vertebrate central nervous system (CNS). The predicted proteins, Plexin B2a and Plexin B2b, contain all the conserved and functional domains of the plexin B-subfamily.

Hyperserotonergic phenotype after monoamine oxidase inhibition in larval zebrafish.

Serotonin (or 5-hydroxytryptamine; 5-HT) and monoamine oxidase (MAO) are involved in several physiological functions and pathological conditions. We show that the serotonergic system and its development in zebrafish are similar to those of other vertebrates rendering zebrafish a good model to study them. Development of MAO expression followed a similar time course as the 5-HT system.

Modulatory neurotransmitter systems and behavior: towards zebrafish models of neurodegenerative diseases.

The modulatory aminergic neurotransmitters are involved in practically all important physiological systems in the brain, and many of them are also involved in human central nervous system diseases, including Parkinson's disease, schizophrenia, Alzheimer's disease, and depression. The zebrafish brain aminergic systems share many structural properties with the mammalian systems. The noradrenergic, serotonergic, and histaminergic systems are highly similar.

Identification of zebrafish histamine H1, H2 and H3 receptors and effects of histaminergic ligands on behavior.

Neuronal histamine regulates several functions in the vertebrate brain. The zebrafish brain contains a widespread histaminergic system and H(3) receptor ligand binding has been reported. In this study we provide evidence for the existence of histamine H(1), H(2) and H(3) receptor genes in zebrafish.