{"id":13017,"date":"2020-06-04T12:01:35","date_gmt":"2020-06-04T10:01:35","guid":{"rendered":"https:\/\/idibell.cat\/?p=13017"},"modified":"2020-06-04T12:01:35","modified_gmt":"2020-06-04T10:01:35","slug":"descobreixen-un-nou-mecanisme-de-plasticitat-homeostatica-en-les-connexions-neuronals-autaptiques","status":"publish","type":"post","link":"https:\/\/idibell.cat\/2020\/06\/descobreixen-un-nou-mecanisme-de-plasticitat-homeostatica-en-les-connexions-neuronals-autaptiques\/","title":{"rendered":"Descobreixen un nou mecanisme de plasticitat homeost\u00e0tica en les connexions neuronals aut\u00e0ptiques"},"content":{"rendered":"<p>Les connexions neuronals, o <strong>sinapsis<\/strong>, no s\u00f3n estables, sin\u00f3 que es van formant i desfent en funci\u00f3 de les necessitats. Aix\u00ed doncs, naixem amb un elevat nombre de sinapsis que eliminem durant l\u2019etapa postnatal, proc\u00e9s necessari pel correcte processament de la informaci\u00f3. El nombre de sinapsis est\u00e0 sotm\u00e8s a un gran control, ja que tant un exc\u00e9s com un defecte pot donar lloc a desequilibris i malalties com l&#8217;esquizofr\u00e8nia o l\u2019autisme<\/p>\n<p>El grup del Dr. Artur Llobet, investigador de l&#8217;Institut d&#8217;Investigaci\u00f3 Biom\u00e8dica de Bellvitge (<a href=\"https:\/\/idibell.cat\/\">IDIBELL<\/a>), la Facultat de Medicina i Ci\u00e8ncies de la Salut i l\u2019Institut de Neuroci\u00e8ncies de la Universitat de Barcelona (<a href=\"http:\/\/www.neurociencies.ub.edu\/\">UBNeuro<\/a>), havia descrit en treballs anteriors la capacitat de la prote\u00efna <strong>SPARC<\/strong>, una prote\u00efna secretada per les c\u00e8l\u00b7lules glials del sistema nervi\u00f3s, per eliminar sinapsis. No obstant aix\u00f2, el mecanisme que utilitzava aquesta prote\u00efna, o quines eren les seves sinapsis diana, encara els hi era desconegut. Per aix\u00f2, van iniciar una s\u00e8rie d&#8217;experiments en qu\u00e8 es deixava actuar SPARC llargs per\u00edodes de temps, amb l&#8217;esperan\u00e7a de detectar quines eren les sinapsis eliminades i per quin mecanisme.<\/p>\n<p>La sorpresa va ser, que en exposar les neurones a l&#8217;acci\u00f3 de SPARC, aquestes inicialment presentaven una caiguda en la neurotransmissi\u00f3, que despr\u00e9s aconseguien recuperar per complet amb SPARC present: \u00a0les neurones manifestaven un nou mecanisme de <strong>plasticitat presin\u00e0ptica homeost\u00e0tica<\/strong>. Aquest tipus de mecanismes s\u00f3n els encarregats de mantenir els nivells de neurotransmiss\u00f3 correctes en els circuits, \u00e9s a dir, ajustar el nombre i pot\u00e8ncia de les sinapsis presents perqu\u00e8 el nivell basal de neurotransmissi\u00f3 sigui constant. El Dr. Llobet assegura &#8220;que anaven a descriure la selectivitat d\u2019acci\u00f3 de SPARC sobre les sinapsis i van acabar investigant un nou mecanisme de plasticitat&#8221;. El treball ha estat publicat a la revista <a href=\"https:\/\/www.nature.com\/articles\/s42003-020-0963-8\"><em>Communications Biology<\/em><\/a>.<\/p>\n<p>Cec\u00edlia Velasco, primera autora del treball, ens explica que els experiments els van realitzar en cultius de neurones a\u00efllades que nom\u00e9s formaven connexions amb si mateixes, les anomenades <strong>sinapsis aut\u00e0ptiques<\/strong>. Aquest tipus de sinapsis van ser descrites en el cervell fa molt de temps. Moltes neurones n\u2019estableixen, per\u00f2 en nombres petits, el que dificulta el seu estudi i fa que la seva funci\u00f3 segui sent essencialment desconeguda. El fet que en els assajos les sinapsis aut\u00e0ptiques es recuperessin tan r\u00e0pidament i amb tanta precisi\u00f3, ens indica que d&#8217;alguna manera les neurones podrien utilitzar aquests contactes per detectar baixades en la neurotransmissi\u00f3, i per tant, generar noves sinapsis per restablir els nivells basals. Segons aix\u00f2, doncs, les sinapsis aut\u00e0ptiques podrien ser un tipus d&#8217;accelerador que augment\u00e9s la neurotransmissi\u00f3 quan fes falta mitjan\u00e7ant la retroalimentaci\u00f3 positiva. Aix\u00ed mateix, el fet que el circuit les recuper\u00e9s amb tanta efic\u00e0cia podria significar que es tracta d&#8217;un tipus de connexions fonamentals per a mantenir l&#8217;equilibri dels circuits neuronals.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Un grup de l\u2019IDIBELL i de la UB demostra que les neurones s\u00f3n capaces de detectar la p\u00e8rdua de sinapsis aut\u00e0ptiques, \u00e9s a dir, aquelles establertes amb elles mateixes, i recuperar la conseg\u00fcent baixada de la neurotransmissi\u00f3 mitjan\u00e7ant la  formaci\u00f3 i potenciaci\u00f3 de noves connexions.<\/p>\n","protected":false},"author":8,"featured_media":13018,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"default","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"categories":[458,340,457],"tags":[],"publishpress_future_action":{"enabled":false,"date":"2024-05-13 01:53:31","action":"change-status","newStatus":"draft","terms":[],"taxonomy":"category"},"_links":{"self":[{"href":"https:\/\/idibell.cat\/wp-json\/wp\/v2\/posts\/13017"}],"collection":[{"href":"https:\/\/idibell.cat\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/idibell.cat\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/idibell.cat\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/idibell.cat\/wp-json\/wp\/v2\/comments?post=13017"}],"version-history":[{"count":0,"href":"https:\/\/idibell.cat\/wp-json\/wp\/v2\/posts\/13017\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/idibell.cat\/wp-json\/wp\/v2\/media\/13018"}],"wp:attachment":[{"href":"https:\/\/idibell.cat\/wp-json\/wp\/v2\/media?parent=13017"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/idibell.cat\/wp-json\/wp\/v2\/categories?post=13017"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/idibell.cat\/wp-json\/wp\/v2\/tags?post=13017"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}