## 2 Results
### Acute Exposure
#### 2.1.6 Neuromolecular Experiments  
We hypothesized that transcriptional changes caused by the organobromines are the underlying mechanisms for the observed modulated neuronal behavior, rather than biochemical modulations. Therefore, we chose 17 genes, either representing different neuronal pathways or because they showed transcriptional changes in the previous performed microarray [7] and are involved in the examined behavior. For detailed information on description and function of the genes, please refer to Table 2. \begin{table}
\begin{tabular}{l l} \hline
**Gene** & **Function** \\ \hline _ace-1_ (abnormal AcetylCholinEsterase) & Acetylcholinesteraseerase \\ _casy-1_ (CAISYntenin/Alcadein homolog) & Learning \\ _che-12_ (abnormal CHEmotaxis) & Chemorezeptor \\ _dat-1_ (DopAmine Transporter) & Dopamine-transporter \\ _dop-1_ (Dopamine receptor) & D1-dopamine-receptor \\ _dop-3_ (Dopamine receptor) & D2- dopamine-receptor \\ _eat-4_ (EATING: abnormal pharyngeal pumping) & Vesicular glutamate transporter \\ _gbb-1_ (GABAB receptor subunit) & GABA-receptor \\ _grd-12_ (GRounDhog (hedgehog-like family)) & Growth and movement \\ _hda-4_ (Histone DeAcetylase) & Histone deacetylase \\ _hen-1_ (HEsitatioN behavior) & Integration of sensory stimuli \\ _mec-10_ (MECHANosensory abnormality) & Mechanical stimulation \\ _srab-6_ (Serpentine Receptor, class AB (class A-like)) & Needed for chemotaxis \\ _tph-1_ (TryPtophan Hydroylase) & Serotonin synthesis \\ _ttx-3_ (abnormal ThermoTaXis) & For AIY interneurons \\ _unc-17_ (UNCoordinated) & Vesicular acetylcholine transporter \\ _unc-47_ (UNCoordinated) & Vesicular GABA transporter \\ \hline \end{tabular}
\end{table} 
Table 2: Description and function of examined genes. Transcription of _ace-1_ tended to increase after exposure to the high concentrations of both organobromines and their mixture, however, no statistical difference to the control could be determined. TBBP-A (0.1 \(\upmu\)M) significantly decreased the transcription of _casy-1_, _gbb-1_, _grd-12_, _trx-3_ and _unc-47_, but increased the transcription of _unc-17_ and _hen-1_. The high concentration of TBBP-A increased the synthesis of several mRNA, except from _eat-4_, were the amount was significantly decreased. DBAA had a similar effect as 0.1 \(\upmu\)M TBBP-A and led to a reduced gene-transcription in many cases. Only _hen-1_, _ace-1_ and _srab-6_ were induced, but in the case of _ace-1_ no significant increase could be detected. Both mixtures induced numerous gene transcriptions. Nevertheless, _eat-4_ and _grd-12_ were repressed by the mixture containing 0.1 \(\upmu\)M TBBP-A and _hen-1_ and _mec-10_ by the mixture containing 50 \(\upmu\)M TBBP-A. For detailed information about the changes in transcription please refer to Table 3.  
With exception of _hen-1_, _srab-6_ and _unc-17_, the mixture containing 0.1 \(\upmu\)M TBBP-A significantly increased the gene-transcription relative to both single compounds. For 50 \(\upmu\)M TBBP-A and DBAA in the mixture a statistical difference to one of the single compounds was observed for nine genes. A statistical difference to both components was never detected.