Axonal sprouting is a form of morphological plastic change of the neurons. It is proposed to underlie long-term changes in brain function and take place even in mature brain. Electriphysiological analysis revealed that chronic stress and antidepressants induce axonal degeneration and sprouting of locus coeruleus noradrenergic neurons in adult rat brain, respectively. Sprouing of hippocampal neurons was represented in the slice cultures of the hippocampus from 1-week old rat. This phenomenon was found to be specific for CA3 pyramidal neurons. Possible molecular mechanisms for neuron-specific morphological plasticity are discussed, referring to results from other laboratories.
Site specific incorporation of unnatural molecules into native proteins are proven to be one of the most promising methodologies in protein molecules engineering. In this article, I describe successful examples of function regulation of hemoproteins by interactions with phenylboronic acid as a sugar recognition site and maleic acids as controlling sites of electrostatic repulsion. As another approach, molecular assemblies such as lipid bilayer membranes, are demonstrated to be potential one which enable the functional conversion of the bound-protein through noncovalent but domain-specific perturbations.