Importance of Biochips in the Study of Neuronal Nicotinic Acetylcholine Receptors

Although tobacco smoking is widespread in the population and some of its toxic effects are widely recognized the mechanisms underlying nicotine addiction and its toxicity still remain poorly understood. An important step toward this understanding was made with functional studies of nicotinic receptors reconstituted in host systems. However, it becomes increasingly important to understand their role in more physiological conditions. Namely, it is mandatory to be able to examine their contribution in a natural neuronal network. One of the best possible approaches would be to dispose of multiple electrode recordings that would allow investigation of acute brain slices. While planar multielectrode arrays constitute one possibility for multiple recordings of neurones in culture their signal noise ratio is, however, not sufficient for acute slices. To overcome this problem we are currently developing a “fakir bed” electrode array in which the electrode tips are brought in closer contact with intact neurones within the slice. In addition to being expressed by neurones, nicotinic acetylcholine receptors are also expressed in other cells throughout the body. For instance it has been shown that white blood cells express significant amount of these proteins and that nicotine can modulate the motility abilities of leukocytes. In a series of experiments we have been able to study these cellular processes in more detail and have established a new biochip technology with the aim of automatic evaluation of cell motility.