As noted earlier, the ADH secreting hypothalamic cells receive two inputs, from baroreceptors and from osmoreceptors
. An increase in plasma volume accompanied by a decrease in osmolality inhibits ADH secretion, while a decrease ha plasma volume accompanied by an increase in osmolality increase ADH secretion (see Table 2).
in the hypothalamus are sensitive to overall fluid balance and release ADH accordingly.
Rather, it seems more likely to be localized in the pathways from the osmoreceptor
neurons to the cortex.
Vasopressin is released once the osmoreceptors
in the hypothalamus detect an increase in serum osmolality or the baroreceptors detect hypovolaemia.
in her hypothalamus stimulated posterior pituitary gland vasopressors to release antidiuretic hormone, in order to increase blood pressure by the renal tubules retaining water (Gutierrez, Reines & Wulf-Gutierrez, 2004).
However, simultaneously with the activation of facilitatory mechanisms, increased activity of osmoreceptors
produced by hyperosmolarity also activates LPBNinhibitory mechanisms, which strongly curb sodium appetite (43,45) (Figure 1).
If you get too little liquid, it's going to shrink your cells, and osmoreceptors
in your brain and other parts of your body are going to sense that cells need water.
in the hypothalamus and heart/blood vessel baroreceptors detect changes in plasma concentrations, producing or reducing anti-diuretic hormone (ADH) concentrations to increase, or decrease water absorption respectively (von Duvillard, 2004).
It appears as though the osmoreceptors
are 'reset' at a lower level to avoid a continuous diuresis.
Another interesting observation is the localization of AQP4 in the neurohypophysis, where osmoreceptors
control the release of ADH by an undefined process.
Two afferent pathways, one from baroreceptors and one from osmoreceptors
, control the secretion of AVP in the presence of hypovolemia or hyperosmolality.
in the hypothalamus itself cause the pituitary to increase ADH levels when plasma osmolality increases as little as 1-2% [2,7] Baroreceptors, especially in the heart and the carotid sinus,  monitor changes in blood volume and pressure and indirectly signal the hypothalamus to regulate ADH according to perceived changes.