but not TRPV4. Despite a significant amount of data, the anatomy of the VOLT is not yet fully comprehended. Function As previously mentioned, the vascular organ of lamina terminalis features neurons responsible for the homeostatic conservation of osmolarity. In addition, the fenestrated vasculature of the VOLT allows the astrocytes and neurons of the VOLT to perceive a wide variety of plasma molecules whose signals may be transduced into other regions of the brain, thereby eliciting autonomic and inflammatory reactions. In experiments, mammalian VOLT neurons were shown to transduce hypertonicity by the activation of the TRPV1 nonselective cation channels. These channels are highly permeable to calcium and are responsible for membrane depolarization and increased action potential discharge. Stated simply, an increase in osmolarity results in a reversible depolarization of the VOLT neurons. This can be seen through the predominantly excitatory effects of ANG on the VOLT through the TRPV1 receptor. In this context, it is worthy to note the VOLT neurons typically feature a resting membrane potential in the range of -50 to -67 mV with input resistances ranging from 65 to 360 MΩ. Despite a solid understanding of the VOLT’s role in the maintenance of body fluid homeostasis, other functions are less understood. For example, it is thought that the VOLT may also play a role in the regulation of LH secretion via a negative feedback mechanism. It is also hypothesized that the VOLT may be the mechanism through which pyrogens function to initiate a febrile response in the CNS. Finally, VOLT neurons have been observed to respond to temperature changes indicating that the organum vasculosum of the lamina terminalis is subject to different climates. Subfornical organ (SFO) Anatomy The subfornical organ is a sensory CVO situated on the underside of the fornix and lacking a BBB, the absence of which characterizes the circumventricular organs. Protruding into the third ventricle of the brain, the highly vascularized SFO can be divided into 3–4 anatomical zones, especially by its capillary density and structure. The central zone is composed exclusively of the glial cells and neuronal cell bodies. Conversely, the rostral and caudal areas are mostly made of nerve fibers while very few neurons and glial cells can be seen in this area. Functionally, however, the SFO may be viewed in two portions, the dorsolateral peripheral (pSFO) division and the ventromedial core segment. As an important mechanism of both energy and osmotic homeostasis,