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An example of upregulation is the response of liver cells exposed to such xenobiotic molecules as dioxin. In this situation, the cells increase their production of cytochrome P450 enzymes, which in turn increases degradation of these dioxin molecules. Downregulation or upregulation of an RNA or protein may also arise by an epigenetic alteration ...
Neural top–down control of physiology concerns the direct regulation by the brain of physiological functions (in addition to smooth muscle and glandular ones). Cellular functions include the immune system’s production of T-lymphocytes and antibodies, and nonimmune related homeostatic functions such as liver gluconeogenesis, sodium reabsorption, osmoregulation, and brown adipose tissue ...
The cells of the neurovascular unit also make up the blood–brain barrier (BBB), which plays an important role in maintaining the microenvironment of the brain. [11] In addition to regulating the exit and entrance of blood, the blood–brain barrier also filters toxins that may cause inflammation, injury, and disease. [12]
Neuroendocrinology is also used as an integral part of understanding and treating neurobiological brain disorders. One example is the augmentation of the treatment of mood symptoms with thyroid hormone. [22] Another is the finding of a transthyretin (thyroxine transport) problem in the cerebrospinal fluid of some patients diagnosed with ...
In rodents for example, neurons in the central nervous system arise from three types of neural stem and progenitor cells: neuroepithelial cells, radial glial cells and basal progenitors, which go through three main divisions: symmetric proliferative division; asymmetric neurogenic division; and symmetric neurogenic division.
These are (1) histone acetylations and histone methylations, (2) DNA methylation at CpG sites, and (3) epigenetic downregulation or upregulation of microRNAs. [11] [12] (See Epigenetics of cocaine addiction for some details.) Chronic nicotine intake in mice alters brain cell epigenetic control of gene expression through acetylation of histones.
Schematic of the HPA axis (CRH, corticotropin-releasing hormone; ACTH, adrenocorticotropic hormone) Hypothalamus, pituitary gland, and adrenal cortex The hypothalamic–pituitary–adrenal axis (HPA axis or HTPA axis) is a complex set of direct influences and feedback interactions among three components: the hypothalamus (a part of the brain located below the thalamus), the pituitary gland (a ...
Some procedures, such as brain biopsies of people with Rett syndrome, usually call for a fresh tissue sample that can only be extricated from the brain of deceased individual. In such cases, the researchers have no control over the age of brain tissue sample, thereby limiting research options.