Tracing the impact of electrophysiological studies of magnocellular neurons

Every neuron in the supraoptic nucleus projects to the neurohypophysis and secretes vasopressin or oxytocin. This simple fact has massively facilitated the study of how oxytocin and vasopressin are made, packaged into neurosecretory vesicles and transported down the axons to the neurohypophysis, and how their secretion is regulated by action potentials. When researchers began using electrophysiology to study the oxytocin and vasopressin cells it was not clear what this could add to the knowledge that came from endocrine studies, but being able to record the electrical activity of identified neuroendocrine neurons during defined physiological challenges made it possible to relate mechanistic understanding to physiological function. Here we study the influence of electrophysiological studies, building a citation network to help explore how our present understanding has been constructed. Our purpose is to try to show what progress is like, and by doing so to talk about impact in a meaningful sense. We focus on fundamental insights attributable to electrophysiological approaches, rather than on electrophysiological features of the neuroendocrine neurons per se, or on findings that have merely confirmed what was known from measurements of hormone secretion.