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Craniopharyngioma
Published in David A. Walker, Giorgio Perilongo, Roger E. Taylor, Ian F. Pollack, Brain and Spinal Tumors of Childhood, 2020
Hermann L. Müller, Claire Alapetite, Jeffrey Wisoff
If the tumor extends into the third ventricle or has a significant retrochiasmatic component, the lamina terminalis is fenestrated. The lamina terminalis is easily distinguished from the chiasm, appearing pale, avascular, and often distended by tumor. As retrochiasmatic tumor is removed, the prechiasmatic space may widen, allowing an additional avenue for dissection.
Distribution and Characteristics of Brain Dopamine
Published in Nira Ben-Jonathan, Dopamine, 2020
The hypothalamus is located below the thalamus and above the pituitary gland (Figure 3.8). It is situated in the ventral diencephalon and is composed of many fiber tracts and discrete nuclei that are positioned symmetrically around the third ventricle. In midsagittal section, the human hypothalamus is bound anteriorly by the lamina terminalis, posteriorly by the posterior commissure at the caudal limit of the mammillary body, and superiorly by the hypothalamic sulcus. The lateral boundaries on each side of the hypothalamus include the internal capsule, cerebral peduncle, and subthalamus. Ventrally, the hypothalamus forms the floor of the third ventricle. Its inferior surface, called the tuber cinereum, contains the median eminence, one of seven circumventricular areas of the brain that have permeable capillaries and are not protected by the BBB.
Summation of Basic Endocrine Data
Published in George H. Gass, Harold M. Kaplan, Handbook of Endocrinology, 2020
Their importance is that they lack a blood-brain barrier and contain fenestrated capillaries which permit neurons to receive substances, including certain hormones, to pass directly between the blood and the brain. Thus, the subfornical organ monitors angiotensin-II levels and projects into the hypothalamus. The area postrema monitors cholecystokinin and projects by lower nuclei to the hypothalamus. The organum vasculosum of the lamina terminalis monitors cytokines in the blood and projects to the brain stem and hypothalamus. The median eminence, pineal gland, and pituitary gland, all of which lack a blood-brain barrier, secrete their own hormones from the central nervous system into the general circulation. Some brain circumventricular organs recognize cytokines in the blood, and if the cytokines are transmitted to the brain, they contribute to the production of fever.2
Genetic identification of preoptic neurons that regulate body temperature in mice
Published in Temperature, 2022
Natalia L. S. Machado, Clifford B. Saper
A second clue came from the literature on fever caused by either lipopolysaccharide or prostaglandin E2. Studies in mice reported that these fever responses were critically dependent upon the expression of the prostaglandin E type 3 (EP3R) receptor by neurons in the preoptic area [12]. These neurons cluster in the MnPO along the along the midline of the ventral part of the preoptic area; as the 3rd ventricle begins to open, they invade the organum vasculosum of the lamina terminalis (OVLT) at the rostral tip of the third ventricle and spill over the lateral margins of the 3rd ventricle at this level (Figure 1). This population also includes neurons along the dorsal surface of the optic chiasm and extending as far as the ventrolateral part of the preoptic area (VLPO). The location of this population of neurons coincides almost precisely with the projection from the parabrachial prodynorophin population [10,13,14].
Basic physiology of the blood-brain barrier in health and disease: a brief overview
Published in Tissue Barriers, 2021
In contrast to the capillaries located in the brain parenchyma, blood microvessels in the circumventricular organs do not display barrier properties. The endothelial cells of these microvessels have fenestrae, which allow the free diffusion of substances between the blood and CNS.37,213,214 These organs consist of secretory structures like pineal gland, subcommisural organ, median eminence, and choroid plexuses and sensory regions, including area postrema, subfornical organ, and organum vasculosum of the lamina terminalis.215 The exchange of hormones and other molecules between the circulation and CNS is accomplished mainly in circumventricular organs in which increased vascularization facilitates the sensory and secretory roles to mediate the communication between the brain and the periphery.215,216
Mechanisms involved in the cardiovascular effects caused by acute osmotic stimulation in conscious rats
Published in Stress, 2020
Eduardo Albino Trindade Fortaleza, Cristiane Busnardo, Aline Fassini, Ivaldo Jesus Almeida Belém-Filho, Gislaine Almeida-Pereira, José Antunes-Rodrigues, Fernando Morgan Aguiar Corrêa
Hypertonic stimulus evokes activation of magnocellular neurons in the SON and PVN nuclei that receive projections from areas involved in the osmoreceptor pathway that regulates body fluid balance, such as the subfornical organ, the organum vasculosum of the lamina terminalis and median preoptic nucleus, as well as limbic structures such as the medial nucleus of the amygdala that sends and receives projections from SON and PVN (Fortaleza, Scopinho, & Correa, 2012b; Fortaleza, Tavares, & Correa, 2009; Kremarik, Freund-Mercier, & Stoeckel, 1993; Larsen & Mikkelsen, 1995; Xiong & Hatton, 1996). Notably, the hypertonic stimulus is a potent releaser of AVP from the posterior pituitary (Dunn et al., 1973; Larsen & Mikkelsen, 1995; Onaka & Yagi, 2001; Shoji et al., 1994; Verney, 1947; Zemo & McCabe, 2002).