Project#1: 5-HT AND LOCOMOTION IN ZEBRAFISH (NSF #0438404)

The goals of this project are:

(1) Mapping of the expression of the new zebrafish 5-HT2 receptor using in-situ-hybridization and immunocytochemical techniques. To identify brain regions or neuron groups that express the new zebrafish 5-HT2 receptor and thus are candidate neuronal populations that participate in the generation and initiation of locomotion, the expression of the receptor will be mapped using in-situ hybridization. With antibodies generated against receptor specific polypeptides of the receptor, we can identify the cellular localization of receptors within neurons. This will be yield valuable information concerning the identity and projection of 5-HT2 expressing neurons within the zebrafish brain and motor pathways.

(2) Pharmacological characterization of the new zebrafish 5-HT2 receptor. The exact identity of the new zebrafish 5-HT2 receptor is still unclear at the present time, but protein sequence data indicate that the receptor is either 5-HT2A- or 5-HT2C-like. Expression of the 5-HT receptor in a mammalian cell line will enable us to perform binding assays and to characterize the receptor pharmacologically.

(3) Identification of 5-HT2 receptor expressing neurons in the motor pathway for pectoral fins. We will perform double labeling experiments of neurons using specific zebrafish 5-HT receptor antibodies and the retrograde tracers to identify neurons in the pectoral motor pathway that participate in the initiation and generation of pectoral fin movements.
The results of the proposed work will allow us to construct a model of the function of 5-HT2 receptors in the initiation and generation of locomotion in the pectoral fin system will lead to a better understanding of mechanisms underlying the orchestration of activity across neuronal populations in a simple vertebrate brain.

Project #2: Serotonin Modulatory Actions on Pectoral Fin Movements. Pectoral fins of larval zebrafish are rhythmically active. Phases of rhythmic movement are interrupted by phases of non-movement. We developed an experimental setup for measuring pectoral fin movements and found that the biogenic amine serotonin modulates pectoral fin activities. Presently, we explore how serotonin effects pectoral motor pathways and circuits. We would like to answer the questions: (1) Which serotonin receptors mediate changes in pectoral fin activities? and (2) Which synapses in the pectoral motor system are modulated by serotonin?

Project #3: Aggressive Behavior in Zebrafish. Our studies revealed that zebrafish can establish dominant hierarchies during a short period of intense fighting. This fighting period is characterized by stereotypic sequences of behavioral patterns such as lateral displays, frontal displays, nipping, and chasing. We would like to answer the questions: (1) How do zebrafish establish dominance hierarchies? and (2) Are neuronal changes associated with changes in the social status of zebrafish?

Students in my laboratory have the opportunity to learn anatomical, physiological, and molecular techniques such as dye-labeling of neurons, extra- and intracellular recording of neuronal activities, Polymerase Chain Reaction, RNA and DNA isolation, cloning of genes, DNA library screening, RACE, immunocytochemistry, and behavioral analysis. The following is a list of projects performed by undergraduate students:

• Neuromodulatory actions of serotonin on pectoral fin movements in larval zebrafish
• Cloning of zebrafish serotonin receptors
• Mapping of dorsal and caudal fin motoneurons
• Mapping of pectoral fin motoneurons
• Fighting behavior in zebrafish

Lab Members

Undergraduate Students

Kate Mittendorf 2007

Michael Forde 2007

Ashley Strahley 2007

Jac Cooper 2006

David Moore 2006

Ashley Strahley 2006

Danielle Brueck 2006

Gregg Wagner 2006

Grace 2006

Lizzy Garland 2005

Erin Andrade 2005

Jesse Williams 2005

Taron Davis 2005

Liz Brack 2005

.........

Christine Heumann 2005

Chrisitine Heumann 2004 (In-situ Hybridization mapping of the expression of a zebrafish 5HT receptor gene)
Marisa Yochum 2004 (In-situ Hybridization mapping of the expression of a zebrafish 5HT receptor gene)
Kala Pattar 2004 (Characterization of a zebrafish 5HT receptor gene and Expression of a 5HT receptor)
Jesse W. Williams 2004 (Identifiaction and cloning of a zebrafish 5HT receptor gene promoter)

Lester Myers 2003 (Characterization of a zebrafish 5HT receptor gene)
Mietra Sadegh 2001/2003 (Mapping of c-fos in zebrafish, Mapping the expression of a 5HT-receptor gene in zebrafish)
Nicholas Opalenik 2000 (Cloning of Zebrafish Serotonin Receptors)
Dan Vollenweider 2000 (Serotonin neuromodulatory actions)
Christopher Clarke 1999, 2000 (Serotonin depletion with 5,7DHT)
Free N. Doecks 1999, 2000 (Serotonin neuromodulatory actions)
Kim H. Eliasz 1999, 2000 (Fighting Behavior in Zebrafish)
Elisabeth Abbiati 1999 (Mapping of pectoral fin motoneurons)
Beth Sulner 1998, 1999 (Mapping of dorsal and caudal fin motoneurons)
Adriane Brown 1998 (Dominance hierarchies in zebrafish)  

Graduate Students

Himali Patel 2003 (Cloning of a zebrafish 5HT receptor)
Hetal Patel 2001 (Cloning of Zebrafish Serotonin Receptors)
Archana Pai 2001 (Cloning of Zebrafish Cannabinoid Receptors)
Luke Fritzky 1999, 2000 (Cloning of Zebrafish Serotonin Receptors)