Temperature dependence of the fluorescence of pyrene labeled crab nerve membranes

Publisher Website
Google Scholar
Abstract
A method, using albumin-pyrene complexes, has been developed for labeling, in a controlled manner, crab leg nerves whose excitability was preserved. The excimer-to-monomer fluorescence intensity ratio of pyrene, embedded in nerve membrane lipids and in their crude lipid extracts, is a fluidity parameter which displayed the following features with temperatures. a—a temperature-dependent increase of fluidity b—three breaks (6°, 19° and 37°C) in the physiological medium c—In Ca ++-depleted sea water, the 37° characteristic temperature vanished. These breaks may reflect some lateral phase separations of the lipid components of nerve membranes. The calcium dependent temperature break may involve a segregation of acidic phospholipids while the other two breaks (6° and 19°C) may be due to neutral lipids phase separation. The relationship of these findings to nerve function is discussed.