User:Wilkinsonre/Galanin

(Exact Text Current Version of specific sections) - 2/29/2020

Tissue distribution
Galanin is located predominantly in the central nervous system and gastrointestinal tract. Within the central nervous system, highest concentrations are found in the hypothalamus, with lower levels in the cortex and brainstem. In the hypothalamus, it is for example found in the ventrolateral preoptic nucleus where it has sleep-promoting function. Gastrointestinal galanin is most abundant in the duodenum, with lower concentrations in the stomach, small intestine, and colon.

Appetite
Injections of galanin into the paraventricular nucleus (PVN) acutely stimulate food intake in rats.

(Draft of New Text) - 2/29/2020

Tissue distribution
Galanin is located predominantly in the central nervous system and gastrointestinal tract. Within the central nervous system, highest concentrations are found in the hypothalamus, with lower levels in the cortex and brainstem. In the hypothalamus, it is, for example, found in the ventrolateral preoptic nucleus where it has sleep-promoting function. Within the brain, galanin has also been found in the ventral forebrain and amygdala. Along with this, the immune reaction of galanin in the brain is centered in the hypothalamopituitary. Gastrointestinal galanin is most abundant in the duodenum, with lower concentrations in the stomach, small intestine, and colon. Galanin is also expressed in the skin where is serves anti-inflammatory functions. Specifically, it has been found in keratinocytes, eccrine sweat glands, and around blood vessels. Galanin has been found in endocrine tumors. Within gastric cancer cells, galanin has been found to have a tumor suppressive role, but hypermethylation has been shown to stop its tumor suppressive properties.

Appetite
Injections of galanin into the paraventricular nucleus (PVN) acutely stimulate food intake in rats. Additionally, injections of galanin into the lateral ventricle of the hypothalamus creates the urge to feed, with a preference for eating fats. Galanin also regulates glucose metabolism and can potentially alleviate symptoms of Diabetes Type II due to its interaction with insulin resistance. Galanin is an inhibitor of pancreatic secretion of insulin.

Addiction
Galanin plays a role in addiction regulation. It is involved in repeated alcohol intake. Along with addiction to alcohol, galanin has been shown to play a role in addiction to nicotine and opiates.

Cognitive Performance
Galanin participates in cognitive performance and has been shown to weaken learning and cognition.

Depression
Noradrenaline and serotonin, two neurotransmitters involved in depression, are both co-expressed and modulated by galanin, suggesting that galanin plays a role in the regulation of depression. Stimulation of the Gal1 and Gal3 receptors result in depression-like behaviors, whereas stimulation of the Gal2 receptor results in reduced depression-like behaviors. Currently, one of the potential mechanisms for this is that galanin stimulates the hypothalamus-pituitary-adrenal axis, which leads to an increase in glucocorticoid secretion. Increased levels of glucocorticoid hormones is common in those who suffer from depression.

Pain and Neuroprotection
Galanin plays an inhibitory role in pain processing, with high doses having been shown to reduce pain. When galanin is added to the spinal core, neuropathic pain is reduced. Along with this, galanin is believed to be effective in reducing spinal hyperexcitability. Sensory neurons increasingly release galanin when they are damaged. An increase in the concentrations of galanin are also believed to be for neuroprotective reasons and lead to promoted neurogenesis. GalR2 activation is believed to mediate the survival role galanin plays in the dorsal root ganglion.

Notes: (not part of draft)
Even though galanin is a neuropeptide, it has been found outside of neurons. Galanin is expressed in keratinocytes, eccrine sweat glands, and around blood vessels. Galanin is produced not only in neuronal cells, but also in non-neuronal skin cells. Galanin has been found in endocrine tumors. Within the brain, galanin has also been found in the ventral forebrain and amygdala.

Galanin regulates glucose metabolism and can potentially alleviate symptoms of Diabetes Type II due to its interaction with insulin resistance. Galanin is an inhibitor of pancreatic secretion of insulin. When galanin is injected into the lateral ventricle of the hypothalamus, the urge to feed is created and shows a preference for eating fats.

Galanin also plays a role in addiction regulation. To date, galanin has been shown to play a role in addiction to alcohol, nicotine, and opiates. Galanin is involved in repeated alcohol intake.

Galanin participates in cognitive performance, mood, and even - in part - control of the pain threshold. Galanin decreases learning and cognition. Agonists of GalR2 are expected to have anticonvulsant and antidepressant effects, which means they could serve as mood stabilizers. Galanin can inhibit glutamate release in the hippocampus.

Galanin serves an anti-inflammatory function in the skin.

The N-terminus of galanin is needed for galanin to perform correctly.

An increase in the concentrations of galanin are believed to be for neuroprotective reasons and lead to promoted neurogenesis. Galanin is increasingly released from damaged sensory neurons. Adding galanin to the spinal cord reduced neuropathic pain. Galanin plays an inhibitory role in pain processing. High doses of galanin have been shown to reduce pain. Galanin is believed to be effective in reducing spinal hyperexcitability. GalR2 activation is believed to mediate the survival role galanin plays in the dorsal root ganglion. Noradrenaline and serotonin, two neurotransmitters involved in depression, are both co-expressed and modulated by galanin, suggesting that galanin plays a role in the regulation of depression. Stimulation of the Gal1 and Gal3 receptors result in depression-like behaviors, whereas stimulation of the Gal2 receptor results in reduced depression-like behaviors. Currently, one of the potential mechanism for this is that galanin stimulates the hypothalamus-pituitary-adrenal axis and therefore increases glucocorticoid secretion.