The presence of a chemical (glutamatergic) synapse in the electroreceptor organ has previously been shown in our laboratory. The question then arises how this voltage-dependent neurotransmission process works in electroreceptors. The electrical signals from the environment are too weak to evoke a significant change in their membrane potentials. In order to generate a physiological change in calcium concentration at the synapse, the cells must amplify the electrical stimulus 100 to 1000 fold! This amplification is most likely an electrical process instigated by ion channels or ion pumps. Therefore, the determination of the ionic channels present in electroreceptor cells is a major key to understanding this process. PhD-thesis-sized subprojects are:
1. A patch clamp study on the nature of the ion channels in the electroreceptor cell membrane.
2. In vitro studies in isolated skin patches, in order to study the electroreceptor cells and the afferent nerve activity separately.
3. A study on the contribution of membrane ATP-ases (ion pumps) to the cell homeostasis, and the coherence of electroreceptor cell clusters.
4. An imaging study on stimulus dependent variations in intracellular free-calcium concentration.
5. A vibrating probe study to relate the resting current of the electroreceptor organs to primary afferent spontaneous activity, and to the ion composition of the environment. |
