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© Helena Johard 2013
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The nervous system is a network of nerve-cells that communicate to coordinate and negotiate our body to internal and external conditions.
A nerve cell recieves chemical messages (neurotransmitters) by receptor molecules that are embedded in the cell membrane. It transmits a message by releasing neurotransmitters.

Insects have long been used as model animals to understand the nervous systems. In my previous research I was investigating a special type of receptors in the blowfly and cockroach brain called insect tachykinin receptors that are related receptors in our nervous system that have many functions for example mediation of pain.

Most organisms have to be prepared for the environmental shifts between night and day, caused by the rotation of the earth. We therefore have an internal clock , coordinated with the night and day periods, that creates the rythmic activity in our body. When we change day and night rhythm our internal clock is out of phase with the external rythm. It takes a time for our clock to reset to the new conditions and that is what happens during jetlag.
I na previous project I was investigating the nerve-cells that create day and night rythmicity in the fruitfly, Drosophila Melanogaster. I researched what transmitter molecules are used for signalling the time and how the signalling pathways look like.
The images below are showing the brain of a fruitfly larvae where the clock cells are labelled in green (green flourescent protein, Timeless-GAL4xUASCD8-GFP).
With the genome projects, where whole genomes of different organisms have been mapped, new genetically based research strategies have emerged.
A commonly used method used in Drosophila is to introduce new genes into the fly genome and create mutant flies. This technique is widely used to study cellular function by targeting them to most commonly produce green flourescent protein, interfering with genetranscription (RNAi) or causing cell deletion.

2009 Johard, H.A.D., Yoishii, T., Dircksen, H., Cusumano, P., Rouyer, F., Helfrich-Förster, C., Nässel, D.R.: Peptidergic clock neurons in Drosophila: ion transport peptide and short neuropeptide F in subsets of dorsal and ventral lateral neurons. J. Comp. Neurol. 516:59-73.

2008 Nässel, D.R., Enell, L.E., Santos, J.G., Wegener, C., Johard, H.A.D. (2008) A large population of diverse neurons in the Drosophila central nervous system expresses short neuropeptide F, suggesting multiple distributed peptide functions. BMC Neurosci.9: 90.

Johard, H. A. D., Enell, L.E., Gustafsson, E.,Trifilieff, P., Veenstra, J. A. and NässeL D., R. Intrinsic Neurons of Drosophila Mushroom Bodies Express Short Neuropeptide F: Relations to Extrinsic Neurons Expressing Different Neurotransmitters. J Comp Neurol. 18;507 (4):1479-1496

2007 Neupert S., Helena A. D. Johard, Nässel, D., R. and Predel, R. Single-Cell Peptidomics of Drosophila melanogaster Neurons Identified by Gal4-Driven Fluorescence. Analytical Chemistry 79 (10): 3690 –3694