The mammalian neurohypophysis consists, almost entirely, of the terminals of magnocellular neurons that reside in the hypothalamus of the brain. In the mouse, some 20,000 magnocellular neurons send their axons, through the infundibular stalk, to the neurohypophysis, where they ramify into approximately 40,000,000 terminals, with an average size of 4-5 microns. Voltage sensitive dyes can be used to record, optically, the action potential as it arrives in the terminals. This voltage change is accompanied by rapid changes in light scattering and intrinsic fluorescence. The intrinsic fluorescence changes are shown to signal the onset of oxidative phosphorylation in the mitochondria of the terminals, and these autofluorescence changes are loosely coupled to the arrival of the action potentials. We will also show that the action potential is accompanied by changes in the diameters of the nerve terminals, changes which have the time courses of the nerve spike, and of exocytosis (secretion of the neuropeptides, oxytocin and vasopressin.)

Profeesor Salzberg obtained his PhD from Harvard University, and after postdoctoral appointments at Harvard and Yale, hsiology & Neuroscience joined the University of Pennsylvania where he is a Full Professor of Physiology & Neuroscience.