ABSTRACT
The remarkable conformational dynamics of DHA are full of surprises and in this chapter we describe a new dimension involving membranes routinely subjected to stretching and bending. Numerous cells and their membranes in the human body are subjected to repeated cycles of stretching often induced by mechanical stress. We de€ne the importance of mechanically stressed membranes here using selected case histories featuring different cells known to be subjected to mechanical stress. Our thick skull protects neurons in the brain from everyday sources of mechanical stress. However, during brain trauma caused by contact sports and war injuries, axons are stretched to a pathological level as discussed in Chapter 16. Axons also stretch to achieve their amazingly fast growth rates. Membranes of synaptic vesicles can be envisioned to be subjected to stretching imposed by their small size and the marked curvature of their membranes. Other membranes likely subject to stretching include sperm tails, cilia, heart muscle cells, and even red blood cells. We propose that the conformational dynamics of DHA and other polyunsaturated fatty acids contribute self-sealing powers to membranes during stretching, in essence conserving ion gradients and saving energy.
