60 YEARS OF NEUROENDOCRINOLOGY: The structure of the neuroendocrine hypothalamus: the neuroanatomical legacy of Geoffrey Harris

Abstract

In November 1955, Geoffrey Harris published a paper based on the Christian A Herter Lecture he had given earlier that year at Johns Hopkins University in Baltimore, MD, USA. The paper reviewed the contemporary research that was starting to explain how the hypothalamus controlled the pituitary gland. In the process of doing so, Harris introduced a set of properties that helped define the neuroendocrine hypothalamus. They included: i) three criteria that putative releasing factors for adenohypophysial hormones would have to fulfill; ii) an analogy between the representation of body parts in the sensory and motor cortices and the spatial localization of neuroendocrine function in the hypothalamus; and iii) the idea that neuroendocrine neurons are motor neurons and the pituitary stalk functions as a Sherringtonian final common pathway through which the impact of sensory and emotional events on neuroendocrine neurons must pass in order to control pituitary hormone release. Were these properties a sign that the major neuroscientific discoveries that were being made in the early 1950s were beginning to influence neuroendocrinology? This Thematic Review discusses two main points: the context and significance of Harris's Herter Lecture for how our understanding of neuroendocrine anatomy (particularly as it relates to the control of the adenohypophysis) has developed since 1955; and, within this framework, how novel and powerful techniques are currently taking our understanding of the structure of the neuroendocrine hypothalamus to new levels.

Bidirectional Anticipation of Future Osmotic Challenges by Vasopressin Neurons

“…Here, we monitored the real-time activity of genetically defined, pituitary-projecting neuroendocrine motor neurons that release vasopressin to control renal water excretion (Bourque, 2008; Nielsen et al, 1995; Sands et al, 2011; Watts, 2015). Using electrophysiological recordings in genetically identified SON pituitary-projecting vasopressin (VP pp ) neurons in water-restricted mice, we observed rapid decreases in spiking within seconds of presentation of cues signaling water availability, beginning prior to water ingestion.…”

“…Neuroendocrine motor neurons (Harris, 1951; Watts, 2015), which release specific hormones into the bloodstream in an activity-dependent manner, also likely play important roles in countering the effects of ingestion on internal homeostasis (Stricker and Hoffmann, 2007; Stricker et al, 2002). However, the extent to which changes in activity in these neurons predict and/or follow the onset of ingestive behavior remains unclear.…”

“…Pituitary-projecting vasopressin (VP pp ) neurons in the supraoptic nucleus (SON) and the paraventricular nucleus (PVH) of the hypothalamus comprise an important class of neuroendocrine neurons (Harris, 1951; Watts, 2015). VP pp neurons react to slow increases in plasma osmolality by releasing the anti-diuretic hormone vasopressin, which acts on the kidney to decrease water excretion (Bourque, 2008; Nielsen et al, 1995; Sands et al, 2011; Watts, 2015).…”

“…VP pp neurons react to slow increases in plasma osmolality by releasing the anti-diuretic hormone vasopressin, which acts on the kidney to decrease water excretion (Bourque, 2008; Nielsen et al, 1995; Sands et al, 2011; Watts, 2015). Previous studies observed decreases in blood vasopressin levels within minutes following water consumption, preceding and hence “anticipating” changes in plasma osmolality (Baertschi and Pence, 1995; Choi-Kwon et al, 1990; Geelen et al, 1984; Huang et al, 2000; Stricker and Hoffmann, 2007).…”

A neural network for intermale aggression to establish social hierarchy

“…The hypothalamus is a highly conserved part of the brain across taxa [117][118][119][120][121] . One of the interesting features of this unit, is that it provides the interface of communication between the brain and the pituitary 122, 123the "master" endocrine gland responsible for the release of numerous hormones necessary for physiological homeostatic regulation [124][125][126][127][128] .…”