Reciprocal Control of Drinking Behavior by Median Preoptic Neurons in Mice

Abstract

Stimulation of glutamatergic neurons in the subfornical organ drives drinking behavior, but the brain targets that mediate this response are not known. The densest target of subfornical axons is the anterior tip of the third ventricle, containing the median preoptic nucleus (MnPO) and organum vasculosum of the lamina terminalis (OVLT), a region that has also been implicated in fluid and electrolyte management. The neurochemical composition of this region is complex, containing both GABAergic and glutamatergic neurons, but the possible roles of these neurons in drinking responses have not been addressed. In mice, we show that optogenetic stimulation of glutamatergic neurons in MnPO/OVLT drives voracious water consumption, and that optogenetic stimulation of GABAergic neurons in the same region selectively reduces water consumption. Both populations of neurons have extensive projections to overlapping regions of the thalamus, hypothalamus, and hindbrain that are much more extensive than those from the subfornical organ, suggesting that the MnPO/OVLT serves as a key link in regulating drinking responses.

Distinct neural mechanisms for the control of thirst and salt appetite in the subfornical organ

“…III.10). However, we can not completely exclude the possibility that the SFO→MnPO pathway was also involved in the control of water intake (Abbott et al, 2016).…”

Role of the median preoptic nucleus in the autonomic response to heat-exposure

“…Our experiments showed that activation of glutamatergic MnPO neurons decreases core temperature substantially, an effect we attributed to cutaneous vasodilatation. In addition to hypothermia, in many animals stimulation also caused water consumption [3], which we found was due to activation of a largely separate set of glutamatergic neurons in the more dorsal part of the MnPO. The hypothermic effect, by contrast, was due to activation of glutamatergic neurons in the avMNPO.…”

“…How glutamatergic MnPO neurons regulate cutaneous blood flow is unclear as these excitatory neurons innervate several brain regions that are thought to promote heat conservation by regulating sympathetic outflow to cutaneous vasoconstrictor neurons (CVC) [3]. One possible route would be that direct projections from glutamatergic MnPO neurons to the DHA/DMH, and the medullary raphe and parapyramidal region, may represent inputs to local inhibitory neurons within these targets that modulate the activity of sympathoexcitatory output neurons [3].…”

“…One possible route would be that direct projections from glutamatergic MnPO neurons to the DHA/DMH, and the medullary raphe and parapyramidal region, may represent inputs to local inhibitory neurons within these targets that modulate the activity of sympathoexcitatory output neurons [3]. Alternatively, inputs from glutamatergic MnPO neurons to inhibitory GABAergic neurons in the lateral preoptic area (LPO) [1][2][3][4][5] and the periaqueductal gray matter may result in inhibition of sympathoexcitatory pathways that conserve heat.…”

Interaction between thermoregulation and osmoregulation in domestic animals

“…Moreover, the neurons in these three sites in the lamina terminalis that were activated by intravenous infusion of hypertonic saline were shown to be directly connected to the vasopressin secreting neurons of the supraoptic and paraventricular nuclei (Oldfield et al, 1994;McKinley et al, 2004) and relayed via thalamic sites to cortical regions involved in the genesis of thirst (Hollis et al, 2008). Recent studies in mice using optogenetic techniques to stimulate or inhibit neuronal populations within the lamina terminalis confirm the importance of the lamina terminalis in regulating water intake (Abbott et al, 2016;Zimmerman et al, 2016).…”