In recent years, three new areas were developed, which use the light for investigation the functions of cells, to control neuronal activity and neuronal networks, to measure the concentration of ions and other cellular compounds, to control the behaviour of living organisms, as well as to search for new ways to treat certain diseases. These areas are optogenetics, optosensorics, and optopharmacology.
Optogenetics – using of photosensitive transmembrane bacterial proteins capable to cause excitation or inhibition of cellular activity under illumination by a different wavelength.
Optosensorics – using specific genetically encoded biosensors for non-invasive analysis of intracellular, concentration of ions and other cytoplasmic components. Biosensors are macromolecular protein constructs that have fluorophore groups capable to change selectively fluorescence upon interaction with specific ions, molecular groups or proteins. Main categories of genetically encoded biosensors are: (a) consisting of a single fluorescent protein sensitive to a specific molecule or ion (single FP-sensors): (b) consisting of two fluorescent proteins and working either on the principle of ratiometric analysis or resonance energy transfer from the donor fluorescent protein to the acceptor (FRET-sensors).
Optopharmacology is based on the ability of certain molecules (azobenzenes, spiropiranes, diarylethenes) to change their conformation upon illumination with the light of a specific wavelength. Optopharmacological compounds are chemical constructs, which consist of: (i) photoswitch, capable to change conformation or charge distribution upon illumination; (ii) molecule capable specifically modulate a function of a target protein, i.e. agonists or antagonists and in some cases (iii) anchor molecule (frequently, maleimide, capable of forming covalent bonds with cysteines), for increasing photochrome specificity. Photochromic molecules represent unique tools for spatially and temporally precise control of numerous biological processes, including neuronal activity. Different types of photoswitchable regulators have been designed and characterized for a large number of ligand-gated receptors in the mammalian nervous system [1,2].
Recent achievements and future perspectives of optopharmacology in the light-induced modulation of receptor-operated channels, as well as optosensoric analysis of ionic transients at synaptic activation of brain slices from transgenic mice will be discussed.
The Sapienza MSC in Neurobiology is a 2-year (120 CFU) full-time Neuroscience study program, with a strong emphasis on training in cutting-edge techniques in all major topics of brain research, from molecules to cognition.