The median preoptic nucleus: front and centre for the regulation of body fluid, sodium, temperature, sleep and cardiovascular homeostasis

Abstract

Located in the midline anterior wall of the third cerebral ventricle (i.e. the lamina terminalis), the median preoptic nucleus (MnPO) receives a unique set of afferent neural inputs from fore-, mid- and hindbrain. These afferent connections enable it to receive neural signals related to several important aspects of homeostasis. Included in these afferent projections are (i) neural inputs from two adjacent circumventricular organs, the subfornical organ and organum vasculosum laminae terminalis, that respond to hypertonicity, circulating angiotensin II or other humoural factors, (ii) signals from cutaneous warm and cold receptors that are relayed to MnPO, respectively, via different subnuclei in the lateral parabrachial nucleus and (iii) input from the medulla associated with baroreceptor and vagal afferents. These afferent signals reach appropriate neurones within the MnPO that enable relevant neural outputs, both excitatory and inhibitory, to be activated or inhibited. The efferent neural pathways that proceed from the MnPO terminate on (i) neuroendocrine cells in the hypothalamic supraoptic and paraventricular nuclei to regulate vasopressin release, while polysynaptic pathways from MnPO to cortical sites may drive thirst and water intake, (ii) thermoregulatory pathways to the dorsomedial hypothalamic nucleus and medullary raphé to regulate shivering, brown adipose tissue and skin vasoconstriction, (iii) parvocellular neurones in the hypothalamic paraventricular nucleus that drive autonomic pathways influencing cardiovascular function. As well, (iv) other efferent pathways from the MnPO to sites in the ventrolateral pre-optic nucleus, perifornical region of the lateral hypothalamic area and midbrain influence sleep mechanisms.

Hierarchical neural architecture underlying thirst regulation

“…However, we showed that individual thirst-related neuronal populations of the lamina terminalis are hierarchically organized, and that MnPO nNOS neurons are the behavioural output neurons. Previous lesion studies in rats and sheep have proposed a model in which the MnPO serves as a critical site that integrates inputs from osmosensory neurons of the SFO and the OVLT 36 – 38 . Our findings well explain and further advance the concept of this model with cell-type-specific precision.…”

Prolactin action in the medial preoptic area is necessary for postpartum maternal nursing behavior

“…In addition to maternal behavior, the MPOA has a number of important homeostatic roles, including thermoregulation, sleep, and social reward (21,22). Potentially, maternal behavior could be impacted if losing the influence of prolactin on these functions also impaired pregnancyrelated adaptations in the maternal brain.…”

Insulin-like growth factor 1 receptor regulates hypothermia during calorie restriction

“…Males: inIGF1RKO, n = 5, and controls, n = 5; females: inIGF1RKO, n = 8, and controls, n = 8. *P < 0.05; **P < 0.01; ***P < 0.001. structures integrating and controlling thermoregulation in the central nervous system (34). Several areas in POA, for instance, ventrolateral preoptic nucleus (35), receive afferents from forebrain circuitry; namely, through the lateral septal nucleus, but also directly from cortical areas.…”