Pharmacokinetics and pharmacodynamics should include in future opto-kinetic and opto-dynamic disciplines. At Stanford, Raag Airan and colleagues developed opsin-receptor chimaeras (the optoXR family) as a new class of retinal-based tools. In a Nature letter, they show that the class of OptoXRs can be functionally expressed in vivo, to permit differential photoactivable control of intracellular cascades with significant impact on the phenotype (i.e., behavior when light was targeted in brain via 200um optical fibers). A green light stimulation (~500 nm, 7 mW/mm2) was sufficient to increase intracellular concentrations of (cAMP, IP3, Ca2+) at levels comparable to those induced by pharmacological stimulation. The use of light, instead of drugs, to modulate network physiology, would be of substantial interest given the versatility of optics to precisely define relevant stimulation times with great control of pulsatile versus tonic modulation. This is also of major concern for synthethic biology, given the wide portfolio of photo-proteins and appropriate light-responsive elements.
Airan, R., Thompson, K., Fenno, L., Bernstein, H., & Deisseroth, K. (2009). Temporally precise in vivo control of intracellular signalling Nature DOI: 10.1038/nature07926