{"id":3185,"date":"2011-01-27T17:19:55","date_gmt":"2011-01-27T15:19:55","guid":{"rendered":"http:\/\/localhost\/azgad\/wordpress\/?p=3185"},"modified":"2011-01-27T23:10:03","modified_gmt":"2011-01-27T21:10:03","slug":"blood-pressure-regulation-just-drink-water","status":"publish","type":"post","link":"https:\/\/azgad.com\/?p=3185","title":{"rendered":"Blood Pressure Regulation? Just Drink Water"},"content":{"rendered":"

.
\nFor 60 years, scientists have puzzled over the possibility of a hepatic
\nosmoreceptor that influences blood pressure regulation. Now,
\nresearchers of the Max Delbr\u00fcck Center for Molecular Medicine (MDC)
\nBerlin-Buch, the Experimental and Clinical Research Center (ECRC)
\nof the MDC and Charit\u00e9 and the Hannover Medical School (MHH)
\nappear to have made a breakthrough discovery. Dr. Stefan Lechner
\nand Prof. Gary R. Lewin (both of MDC), Professor Friedrich C. Luft
\n(ECRC) and Professor Jens Jordan (ECRC; now MHH) have
\ndiscovered a new group of sensory neurons in the mouse liver
\nwhich mediates the regulation of blood pressure and metabolism.
\nThis peripheral control center outside of the brain is triggered simply
\nby drinking water and leads to an elevation of blood pressure in sick
\nand elderly people. (Neuron, Vol. No. 69 (2) pp. 332-344).
\n.
\nMore than ten years ago Professor Jens Jordan, MD, then a research
\nfellow at Vanderbilt University in Nashville, Tennessee, observed a
\nphenomenon together with his colleagues, more or less by accident.
\nLater, at the former Franz Volhard Clinic of the Charit\u00e9 in Berlin-Buch,
\nJens Jordan again observed that in patients with a damaged nervous
\nsystem, blood pressure readings rose by as much as 50 mm Hg if
\nthe patients drank a half liter of water all at once. \u201cIn young people
\nwhose sympathetic nervous system was stimulated by drugs, water
\nintake also caused blood pressure levels to rise,\u201d said Professor
\nFriedrich C. Luft of the ECRC. \u201cEven in healthy older people, water
\ndrinking triggers a regulator for blood pressure.\u201d The two clinicians
\ninvited neuroscientists at MDC to collaborate with them and started
\na joint research project.
\n.
\nFor 60 years researchers have suspected that there must also be a
\ncontrol center for the body\u2019s self-regulation located outside of the brain.
\nMotivated by findings of recent studies, the researchers in Berlin-Buch
\ntherefore looked for sensory neurons specifically in organs peripheral
\nto the central nervous system that would detect body changes caused
\nby water intake and would thus be able to activate a regulator which
\nin old and sick people causes blood pressure to rise and which stimulates
\nmetabolism in healthy young people.
\n.
\n.
\n.photo will be added later<\/strong>.
\n.
\n.
\nPressor Reflex Triggered by Water Intake In humans, a pressor reflex is
\ntriggered simply by drinking tap water. After passing through the esophagus
\nand stomach, the water is absorbed by the small intestine and is then swept <\/em>
\non towards the liver in portal vein blood. MDC-scientists and their clinical
\npartners have now found a new population of osmoreceptors in the liver,
\nwhich detect the slightest physiological shifts in blood osmolality, a specific
\nmeasure of the human water balance. If the osmolality decreases below its
\nset point, the osmoreceptors send an electrical signal. This signal triggers
\nan action potential, which in turn stimulates the hepatic vessels to raise
\nblood pressure. (Graphic: Dr. Stefan Lechner\/ Copyright: MDC)
\n.
\n.
\n\u201cIn this entire process, osmolality plays a key role,\u201d explained Dr. Stefan
\nLechner, a member of Professor Lewin\u2019s research group. \u201cIt is the
\nmeasure of the body\u2019s water balance. And it indicates how many
\nmolecules are dissolved in a liter of fluid. Each species has a characteristic
\nset point for osmolality, which depends to a great extent on the immediate
\nliving conditions. We wanted to know how deviations of osmolality are
\nable to activate a regulator.\u201d
\n.
\nThe researchers observed in the mouse model that specific neurons in the
\nliver react actively to water intake. The water the mice drink is absorbed
\nin the small intestine and reaches the blood system via the liver. Due to
\nthe sudden water intake, the osmolality in the blood vessels of the liver
\nfalls under its set-point value. This deviation is registered by sensory neurons
\nin the liver, the so-called osmoreceptors, as the researchers could
\nnow demonstrate. They found that the osmoreceptors transform the information
\ninto an electrical signal, which in turn triggers a reflex and stimulates the
\nhepatic blood vessels to raise blood pressure.
\n.
\nIon Currents Help to Elucidate the Mechanisms <\/strong>
\n.
\nTo study the activation of the osmoreceptors under realistic physiological
\nconditions, the researchers stained this newly discovered group of
\nosmoreceptors in the liver with a dye. In their experiments they could
\nthus show that after drinking water, even the slightest shifts of osmolality
\nin the blood flowing through the liver activate nerve fibers in the liver and
\ncause ion currents to flow. The ion currents were similar to those that
\ncan be measured in an ion channel located both in the central nervous
\nsystem and in the internal organs (heart, liver, kidney, testicles, pancreas).
\nThis ion channel, abbreviated TRPV4, reacts very sensitively to changes
\nand functions quasi as an osmoreceptor.
\n.
\n\u201cThe TRPV4 ion channel opens in just a few hundred milliseconds like the
\nlens of a camera, letting the electrical signal through and thus activating a
\nregulator,\u201d explained Dr. Stefan Lechner. \u201cWe were now interested in
\nwhether the TRPV4 ion channel is acting alone or whether it needs subunits
\nto aid it, and we wanted to know how the whole thing works mechanically.\u201d
\n.
\nIn further experiments, to elucidate the role and function of TRPV4 in this
\nregulation process, the researchers studied mice in which the gene for the
\nTRPV4 ion channel had been inactivated. After giving these knockout mice
\nwater to drink, they did not observe any activation of the osmoreceptors
\nin the liver. No ion currents flowed and as a consequence, no reflex was
\ntriggered. The researchers concluded that the elevation of the blood
\npressure due to water intake must be associated with the presence of the
\nTRPV4 ion channel.
\n.
\nConsequences for therapy<\/strong>
\n.
\n\u201cWe are now able to describe the characteristics of a completely new
\ngroup of hepatic osmoreceptors on the molecular level, which in humans
\nare possibly an extension of a very important regulating reflex,\u201d said
\nProfessor Lewin. \u201cThe research findings not only improve our understanding
\nof the physiological role of osmoreceptors in mediating blood pressure,
\nmetabolism and osmolalic self-regulation, over the long term they could
\nalso lead to new strategies in the treatment of diseases caused by the
\nabsence of the gene encoding the TRPV4 channel protein.\u201d
\n.
\n\u201cThe effect of drinking water on blood pressure regulation is already
\nleading to therapeutic consequences in the daily routine of the hospital,\u201d
\nProfessor Jordan added. "We tell patients to drink water who, due to blood
\npressure regulation disorders, suffer from fainting attacks when standing.
\nThis alleviates the symptoms and at the same time we are able to reduce
\nthe amount of medication. Healthy people can also suffer fainting attacks
\nwhen they stand for a long time or are otherwise under strain, e.g.
\nwhen they donate blood. In many cases these can be avoided by drinking
\nwater. Our decade-long persistence in investigating osmolalic self-regulation
\nhas really paid off!\u201d
\n.<\/p>\n

Pressor Reflex Triggered by Water Intake In humans, a pressor reflex is
\ntriggered simply by drinking tap water. After passing through the esophagus
\nand stomach, the water is absorbed by the small intestine and is then swept
\non towards the liver in portal vein blood. MDC-scientists and their clinical
\npartners have now found a new population of osmoreceptors in the liver,
\nwhich detect the slightest physiological shifts in blood osmolality, a specific
\nmeasure of the human water balance. If the osmolality decreases below its
\nset point, the osmoreceptors send an electrical signal. This signal triggers
\nan action potential, which in turn stimulates the hepatic vessels to raise
\nblood pressure. (Graphic: Dr. Stefan Lechner\/ Copyright: MDC)
\n.
\n.<\/p>\n","protected":false},"excerpt":{"rendered":"

. For 60 years, scientists have puzzled over the possibility of a hepatic osmoreceptor that influences blood pressure regulation. Now, researchers of the Max Delbr\u00fcck Center for Molecular Medicine (MDC) Berlin-Buch, the Experimental and Clinical Research Center (ECRC) of the MDC and Charit\u00e9 and the Hannover Medical School (MHH) appear to have made a breakthrough … <\/p>\n

\u05d4\u05de\u05e9\u05d9\u05db\u05d5 \u05d1\u05e7\u05e8\u05d9\u05d0\u05d4<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[10],"tags":[513,186,191],"class_list":["post-3185","post","type-post","status-publish","format-standard","hentry","category-10","tag-513","tag-186","tag-191","nodate","item-wrap"],"_links":{"self":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/3185","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3185"}],"version-history":[{"count":9,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/3185\/revisions"}],"predecessor-version":[{"id":3196,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/3185\/revisions\/3196"}],"wp:attachment":[{"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3185"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3185"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3185"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}