title: 60 YEARS OF NEUROENDOCRINOLOGY: The posterior pituitary, from Geoffrey Harris to our present understanding.
abstract: Geoffrey Harris pioneered our understanding of the posterior pituitary, mainly with experiments that involved the electrical stimulation of the supraoptico-hypophysial tract. In the present essay, we explain how his observations included clues to the pulsatile nature of the oxytocin signal - clues that were followed up by subsequent workers, including his students and their students. These studies ultimately led to our present understanding of the milk-ejection reflex and of the role of oxytocin in parturition. Discoveries of wide significance followed, including: the recognition of the importance of pulsatile hormone secretion; the recognition of the importance of stimulus-secretion coupling mechanisms in interpreting the patterned electrical activity of neurons; the physiological importance of peptide release in the brain; the recognition that peptide release comes substantially from dendrites and can be regulated independently of nerve terminal secretion; and the importance of dynamic morphological changes to neuronal function in the hypothalamus. All of these discoveries followed from the drive to understand the milk-ejection reflex. We also reflect on Harris's observations on vasopressin secretion, on the effects of stress, and on oxytocin secretion during sexual activity.
authors.affiliation: Centre for Integrative PhysiologyUniversity of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH9 8XD, UK Gareth.Leng@ed.ac.uk.
authors.forename: Gareth
authors.initials: G
authors.lastname: Leng
authors.affiliation: Centre for Integrative PhysiologyUniversity of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH9 8XD, UK.
authors.forename: Rafael
authors.initials: R
authors.lastname: Pineda
authors.affiliation: Centre for Integrative PhysiologyUniversity of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH9 8XD, UK.
authors.forename: Nancy
authors.initials: N
authors.lastname: Sabatier
authors.affiliation: Centre for Integrative PhysiologyUniversity of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH9 8XD, UK.
authors.forename: Mike
authors.initials: M
authors.lastname: Ludwig
mesh_terms: D000818:Animals; D005260:Female; D006801:Humans; D008893:Milk Ejection / Q000502:physiology*; D010121:Oxytocin / Q000502:physiology*; D036801:Parturition / Q000502:physiology*; D010904:Pituitary Gland, Posterior / Q000502:physiology*; D014667:Vasopressins / Q000502:physiology*
chemical_list: D014667:Vasopressins; D010121:Oxytocin
keywords: oxytocin; physiology; pitutitary; vasopressin