PLoS One. 2014 Jul 29;9(7):e102524. doi: 10.1371/journal.pone.0102524. I-eCollection ka-2014.
Abstract
Ukuvezwa okungapheliyo kwe-cocaine kubo bobabini abantu abakhotyokisiweyo kunye neemodeli ze-rodent zokulutha kunciphisa umsebenzi we-cortical wangaphambili, othi emva koko ulawule ukusetyenzwa komvuzo kunye nomsebenzi wolawulo oluphezulu. Isiphumo esishiyekileyo sesi sithintelo sokuziphatha sikhuthaza ukuba sesichengeni sokubuyela umva. Ngaphambili siye sabonisa ukuba ukonyuka okubangelwa yi-cocaine kwi-brain-derived neurotrophic factor (BDNF) intetho kwi-medial prefrontal cortex (PFC) yindlela ye-neuroadaptive eyenza ukuba i-cocaine isebenze. Njengoko i-BDNF yaziwa ngokuchaphazela ukusinda kwe-neuronal kunye ne-synaptic plasticity, siye savavanya i-hypothesis yokuba ukuyeka ukuzilawula kwe-cocaine kuya kukhokelela kutshintsho kwi-neuronal morphology kunye noxinaniso lwe-synaptic kwi-PFC. Ukusebenzisa ubuchule benoveli, uluhlu lwe-tomography kunye ne-Golgi staining, utshintsho lwe-morphological kwi-rat PFC lwahlalutywa emva kweentsuku ezili-14 zokuzilawula kwe-cocaine kunye neentsuku ezisi-7 zokuziyeka ngenkani. Iziphumo zethu zibonisa ukuba i-dendritic branching iyonke kunye ne-synaptic density iyonke iyancipha kakhulu kwi-rat PFC. Ngokwahlukileyo koko, ukuxinana kwee-dendritic spines ezibhityileyo zonyuka kakhulu kumaleko we-V pyramidal neurons we-PFC. Ezi ziphumo zibonisa ukuba utshintsho oluguquguqukayo lwesakhiwo lwenzeka ngexesha lokuyeka i-cocaine enokuthi ibe negalelo ekubonweni komsebenzi we-PFC kubantu abalikhoboka le-cocaine.
intshayelelo
Utshintsho kulwakhiwo lweplastikhi ngaphakathi komvuzo wesekethe kucetywa ukuba zibe ziindlela eziphambili ezinegalelo kubuchule obunamandla be-cocaine bokugcina isimilo sokufuna iziyobisi (ihlaziywe kwi. [1]). Izifundo zangaphambili zibonise ukonyuka kwe-dendritic arborization kunye noxinaniso lomqolo kwi-nucleus accumbens (NAc) [2]-[4], indawo ye-ventral tegmental [5]kunye ne-prefrontal cortex (PFC) [6] emva kokuba sesichengeni secocaine. Ngelixa uninzi lwezifundo lujolise kutshintsho lwesakhiwo olunxulumene nomsebenzi ongasebenziyo we-NAc, zimbalwa kakhulu izifundo ezivavanye utshintsho kwi-PFC. Imigca emininzi yobungqina ibonisa ukungasebenzi kwe-PFC kulandela ukuvezwa okungapheliyo kwe-cocaine kuwo omabini amakhoboka abantu. [7], [8] kunye neemodeli zeempuku zokulutha [9], [10]. Ke ngoko, ukubonakalisa utshintsho lwesakhiwo olwenzeka kwi-PFC lufanelekile ekuqondeni iziganeko zemolekyuli ezenza umlutha.
I-PFC ilawula ukulawulwa kwempembelelo kunye nokwenziwa kwezigqibo kwaye ke idlala indima ebalulekileyo kwisakhono somntu sokulawula ukuziphatha, ngakumbi ekuxhomekeke kwiziyobisi. [8], [11]. Umzekelo, kubantu abakhotyokiswe yi-cocaine, ukwehla kokusebenza kwe-prefrontal cortex kunxulunyaniswa nokurhoxiswa kweziyobisi kunye nokuphazamiseka kweempendulo eziphezulu zolawulo. [7], [8], nto leyo enokwandisa ukuba sesichengeni sokubuyela umva. Kwiimpuku, ukwanda komsebenzi we-neuronal kwi-PFC kunxulunyaniswa nokutya kwe-cocaine [9], [10], ukuziphatha kakubi ngokufuna iziyobisi [12], kunye nokubuyiselwa kwecocaine emva kokurhoxa [13]-[15]. Ukongeza, ukuqina kwe-membrane kupheliswa kwi-PFC kulandela ulawulo olungapheliyo lwe-cocaine [16]. Okokugqibela, umsebenzi we-metabolic owenziwe ngamachiza kwi-PFC ubotshwe kwiimpuku ezilawulwa inaliti yomngeni ngexesha lokurhoxa kulawulo lwe-cocaine. [9], [17]. Ngokudibeneyo, olu phando lubonisa ukuba i-cocaine engapheliyo idala utshintsho olunzulu olusebenzayo kwi-PFC enokuthi inyanyaniswe nokonyuka kwenani le-synapses ezithintelayo kunye / okanye ukuncitshiswa kwe-synapses evuselelayo kwi-PFC. Nangona kunjalo, iinguqu ze-morphological ezenzeka kwi-PFC emva kokusetyenziswa kweziyobisi ezingapheliyo azikacaciswanga.
Kolu phononongo lwangoku sifuna ukuvavanya ukuba ukuziyeka kwi-cocaine kukhokelela kutshintsho lwesakhiwo kwi-PFC. Ukuguqulwa kwe-morphological kuhlolwe kusetyenziswa indlela yendabuko, i-Golgi staining, kunye ne-novel technique, i-array tomography. I-Array tomography yindlela ekhethekileyo edibanisa i-ultrathin tissue sectioning kunye ne-immunofluorescence kunye nokwakhiwa kwakhona kwemifanekiso emithathu-ntathu ukuvumela ubungakanani obuchanekileyo kunye nohlobo oluthile lwe-synapse density. [18], [19]. Ukusebenzisa ezi ndlela, iziphumo zethu zibonise iplastiki enkulu kwi-PFC yegundane ekuphenduleni kwifom yokuyeka i-cocaine.
Impahla nenkqubo
Izilwanyana kunye nendawo yokuhlala
Iigundane ze-Sprague-Dawley zamadoda (i-Rattus norvegicus) ezinobunzima be-250-300 g zifunyenwe kwi-Taconic Laboratories (eGermantown, NY). Izilwanyana zahlaliswa ngokutya kunye namanzi afumaneka kwi-ad libitum kwikhaya labo. Iiprothokholi zokulinga zonke zazihambelana nezikhokelo ezikhutshwe yi-US National Institutes of Health kwaye zavunywa yi-Perelman School of Medicine kwiYunivesithi yasePennsylvania kunye neYunivesithi yasePennsylvania ye-Institutional Animal Care and Use Committee.
Ukuhlinzwa
Ngaphambi kokuhlinzwa, iigundane zahlanjululwa nge-80 mg / kg ketamine kunye ne-12 mg / kg xylazine (ip; Sigma-Aldrich, St. Louis, MO). I-catheter ye-silastic ehlala ngaphakathi (i-diameter yangaphakathi yi-0.33 mm, i-diameter yangaphandle eyi-0.64 mm) yafakwa kwi-jugular vein yasekunene kwaye yafakwa endaweni. I-catheter yayigqithiswa ngaphantsi kwe-subcutaneously phezu kwe-blade blade kwaye ihanjiswe kwi-platform ye-mesh backmount (i-CamCath, i-Cambridge, i-UK) eyayifakwe ngaphantsi kwesikhumba ngokuthe ngqo ngaphezu kwe-scapulae. I-Catheters yahlanjululwa imihla ngemihla kunye ne-0.3 ml ye-antibiotic ye-Timentin (i-ticarcillin disodium / i-potassium clavulanate, i-0.93 mg / ml; u-Henry Schein, uMelville, NY) echithwe kwi-saline ye-heparinized (10 U / ml). Iicatheter zavalwa ngeplastiki obturator xa zingasetyenziswa.
Ukuzilawula kwecocaine
Iimpuku zavunyelwa iintsuku ezisi-7 ukuba zibuyele kuqhaqho ngaphambi kokuba kuqale ukuzilawula kwe-cocaine. Iimpuku zabelwa ngokungenamkhethe kwelinye lamaqela amabini: izilwanyana ezizilawulayo ngecocaine kunye nolawulo lwetyuwa edyokhweni. Impuku nganye eqeqeshelwe ukuphendula ukunyanzeliswa kwe-cocaine edibeneyo yadityaniswa nesihloko esifakwe edyokhweni esifumene inani elifanayo kunye nepateni yethutyana ye-infusions njengoko ilawulwa yi-rat yovavanyo lwe-cocaine. I-Lever yokucinezela iimpuku ezifakwe edyokhweni yetyuwa yayingenazo iziphumo ezicwangcisiweyo.
Ekuqaleni, iimpuku zovavanyo lwe-cocaine zafakwa kumagumbi asebenzayo emodyuli (iMed Associates, iSt. Albans, VT) kwaye yavunyelwa ukuba icinezele i-lever ye-cocaine ye-intravenous infusions (0.25 mg cocaine/59 µl saline, infusion over 5 s) kwindawo emiselweyo- umlinganiselo we-1 (FR1) ishedyuli yokuqiniswa. Nje ukuba igundane lovavanyo lwe-cocaine lizuze ubuncinci i-20 infusions ye-cocaine kwiseshoni enye yokusebenza phantsi kweshedyuli ye-FR1, imfuno yokuphendula yatshintshelwa kwishedyuli ye-FR5 yokomelezwa. Ukuphendula kuzo zombini iishedyuli ezimiselweyo, elona nani liphezulu le-cocaine infusions lalinqunyelwe kwi-30 ngeseshoni yolawulo lwemihla ngemihla kunye nexesha le-20 s lokuphuma lilandela ukufakwa kwe-cocaine nganye, ngelo xesha iimpendulo ze-lever ezisebenzayo zabhalwa kodwa zingenaziphumo zicwangcisiweyo. . Iiseshoni zemihla ngemihla zeeyure ezi-2 (iintsuku ezisi-7/iveki) zaqhutywa zizonke iintsuku ezili-14. Iimpendulo ezenziwe kwi-lever engasebenziyo, engenazo iziphumo ezicwangcisiweyo, nazo zabhalwa ngexesha leeseshoni zoqeqesho ze-FR1 kunye ne-FR5.
Emva kwe14th Iseshoni yokusebenza yemihla ngemihla, i-cocaine-yovavanyo kunye neegundane zokulawula i-saline edyokhweni zabuyiselwa kwiikheji zabo zasekhaya apho baye bahamba iintsuku ze-7 zokuyeka iziyobisi ngenkani. Ngo7th Ngomhla wokuyeka i-cocaine, ubuchopho basuswa kwaye i-PFC yachithwa emkhenkceni. Iintsuku ezisixhenxe zokuyeka i-cocaine zakhethwa ukuze zenze uthelekiso oluthe ngqo kuphononongo lwethu olupapashwe ngaphambili oluvavanya utshintsho olwenziwe yi-cocaine kwi-PFC BDNF. [20].
Ingqinisiso
Amagundane ayenziwe i-anesthesized (100 mg / kg, ip sodium pentobarbital) kwaye i-perfused nge-ice-cold 4% paraformaldehyde kwi-0.1 M PB, pH 7.4 (PFA). Ihemisphere enye esuka kwingqondo nganye yayisetyenziselwa ukudyobha igolgi kunye nenye ihemisphere kwiarray tomography. Ii-hemispheres ze-Array zilungiswe emva kwe-4% ye-PFA kunye ne-2.5% ye-sucrose kwiiyure ze-2 kunye ne-Golgi hemispheres zifakwe kwi-48 h kwi-4% PFA.
Uluhlu lweTomography
Uvavanyo lwe-array tomography lwenziwa njengoko kuchaziwe ngaphambili [19], [21]. Ngokufutshane, i-PFA izicubu ezisisigxina zifakwe kwi-resin kunye ne-coronal (70 nm) amacandelo kwinqanaba le-mPFC zaye zanqunyulwa kwaye zaqokelelwa njengeribhoni. Iiribhoni zifakwe i-hydrated kwi-50 mM glycine e-Tris kwaye ivalwe kwisisombululo sokuthintela (0.05% Tween/0.1% ye-bovine serum albumin kwi-Tris buffer (50 mM Tris/150 mM NaCl, pH 7.6). I-Chemicon), i-PSD65 (i-Cell Signaling), okanye i-synaptophysin (i-Abcam), kwisisombululo sokuthintela ubusuku bonke kwi-95 ° C. Iibhobhoni zihlanjwe nge-Tris buffer kwaye zihlanjululwe kunye ne-antibodies yesibini kwi-4.![[umyinge]](http://www.ncbi.nlm.nih.gov/corehtml/pmc/pmcents/x2236.gif){kind=small}
I-50 kwisisombululo sokuthintela (ibhokhwe ye-anti-mouse Alexa-flour 488 kunye nebhokhwe echasene nomvundla i-cy3 okanye idonki i-anti-rabbit cy5). Iiribhoni zichanekile nge-DAPI ukuququzelela ukufumana iisayithi ezifanayo kwicandelo ngalinye. Imifanekiso ye-tile-scan yaqokelelwa kusetyenziswa i-microscope ye-Zeiss AxioImager Z2 epifluorescence. Imifanekiso evela kwindawo efanayo kwinqanaba ngalinye le-20-30 yeribhoni nganye ifunyenwe kwi-63x kunye neenkqubo ezizenzekelayo ezikhethekileyo kwi-array tomography.
Uhlalutyo lwe-Array Tomography
Imifanekiso elandelelanayo evela kwiribhoni nganye yavulwa ngokulandelelanayo, yaguqulelwa kwi-stack kwaye ihambelana neeplagi ze-MultiStackReg kunye ne-StackReg (ngemali ye-B. Busse kwiYunivesithi yaseStanford kunye [21], [22]. Iibhokisi zezityalo (19.5 µmx19.5 µm) zazisetyenziselwa ukukhetha imimandla enomdla (ROI) kwi-neuropil yobungakanani. Ukhetho kwafuneka lungabandakanyi imizimba yeeseli ze-neuronal okanye ezinye izinto ezifihlakeleyo. Uhlalutyo lomfanekiso oluzenzekelayo, izityalo ezinomdla (okanye i-ROIs) ye-synaptophysin, i-glutamic acid decarboxylase-65 (GAD65) kunye ne-PSD95 zaye zaveliswa ngokuzenzekelayo ngokulandelelana kunye ne-algorithms ezenzekelayo kwi-ImageJ. Izityalo zafakwa ikhowudi kwaye uhlalutyo lwaqhutywa lungaboni kwimeko. I-automated, i-threshold-based search programme ukulinganisa inani le-puncta echongiweyo njenge-positive synapses isetyenziswe njengoko bekuchaziwe ngaphambili. [23]. Uxinaniso lweetheminali ze-presynaptic, iitheminali ze-postsynaptic ze-excitatory, kunye nepesenti ye-GAD-positive (inhibitory) synapses zibalwe kumyinge weendawo zesampulu ezingama-75 ngesilwanyana ngasinye esiqokelelwe kwiibhloko ezimbini zethishu ezahlukeneyo kwi-PFC (n
=I-cocaine enyangwayo ezi-5, izilwanyana ezinyangwa ngetyuwa ezi-5) iyonke eyi-29,154 ye-postsynaptic puncta kunye ne-53,565 ye-presynaptic puncta ukusuka kwiindawo ezingama-818 zesampulu kuzo zonke izilwanyana ezinyangwa ngetyuwa ezi-5 kunye ne-29,662 ye-postsynaptic kunye ne-17,034 ye-presynaptic puncta ukusuka kwiindawo ezingama-588 zesampulu. Amaxabiso aphakathi oxinaniso lwe-synapse kunye nepesenti ye-inhibitory synapses kwisilwanyana ngasinye zibaliwe kwaye ii-t-tests ziqhutywa kusetyenziswa i-medians yezilwanyana ukuvavanya ukuba kukho umahluko phakathi kweendlela zeqela.
Indlela ye-Rapid-Golgi
Icandelo elinye iGolgi staining yenziwa njengoko bekuchaziwe ngaphambili [24], [25]. Ngokufutshane, i-mPFC esuka kwi-hemisphere enye yesilwanyana ngasinye yasikwa kwii-100 µm ze-coronal amacandelo kunye ne-post-fixed kwi-1% ye-osmium tetraoxide elandelwa ngokuhlamba okuthathu kwi-0.1 M PB, pH 7.4. Amacandelo afakwe kwi-3.5% ye-potassium dichromate ngobusuku, ahlanjwe ngokufutshane kwaye afakwe nge-1.5% ye-nitrate yesilivere ngendlela yesandwich. [25]. Amacandelo afakwe kwi-gelatin-coated slides kunye ne-20% ye-sucrose kwaye yaphelelwa ngamanzi ngoluhlu lwe-alcohol concentrations elandelwa yi-de-fatting kwi-xylene kunye nokugubungela.
Uhlalutyo lweGolgi
Izilayidi zeGolgi zabhalwa kwaye zahlalutywa zingaboni kwimeko kwaye zonke zahlalutywa ngumlingi ofanayo. Imifanekiso ye-Neuronal kunye ne-tracings kunye nemifanekiso emele i-dendritic spines yaqokelelwa kusetyenziswa i-microscope ye-BX51 ye-Olympus ethe tye kunye nesiteji esidibeneyo semoto (i-Prior Scientific, Rockland, MA) kunye nenjongo ye-20 × 0.7 NA. Uhlalutyo lwe-dendritic branching, i-7 neurons yakhethwa ukuhlalutya ngesilwanyana ngasinye. Silinganise ubude be-neurite kunye nobunzima sisebenzisa i-macros NeuronJ kunye ne-Advanced Sholl Analysis, ngokulandelanayo. Inani lee-intersections (amanqaku esebe) phakathi kwezangqa ezigxininisiweyo kwi-radii phakathi kwe-5-250 µm (kuquka i-basal kunye ne-apical dendrites) zilinganiswe kwaye zithelekiswa phakathi kwamaqela. Uhlalutyo lwe-spine density, i-4-5 iinqununu ubuncinane ze-20 µm ubude ukusuka kwi-oda yesithathu ye-basal dendrites yahlalutywa nge-neuron ukusuka kwi-5-7 neurons kwisilwanyana ngasinye usebenzisa i-microscope ye-Zeiss AxioImager Z2 epifluorescence ene-63x injongo yokucwiliswa kweoli. I-Spine morphology yahlelwa njengoko kuchaziwe ngaphambili [26]. Ubuninzi bomnqonqo we-linear segment nganye ye-dendritic kunye ne-spine morphology (encinci, i-stubby, i-mushroom, i-cup-shaped) yomqolo ngamnye yathelekiswa phakathi kwamaqela. Isoftware yomthombo ovulekileyo evela kumaZiko ezeMpilo eSizwe (ImageJ) yayisetyenziselwa iGolgi kunye ne-array tomography data analysis.
iziphumo
Ukuyeka ukusebenzisa i-cocaine kunciphisa ubuninzi be-synapse
I-Array tomography yayisetyenziselwa ukulinganisa utshintsho kuzo zombini i-synapses evuselelayo kunye ne-inhibitory ukuze kuqinisekiswe utshintsho oluthile lwe-morphological olwenzeka kwi-PFC ekuphenduleni ukuyeka ukuzilawula kwe-cocaine. I-Array tomography yindlela ephezulu yokutyhutyha evumela ubungakanani obuchanekileyo be-synapses iyonke, inhibitory, kunye ne-excitatory synapses kwizakhiwo ezincinci kakhulu ukuba zichongwe ngokufanelekileyo okanye zendawo ngeendlela ze-confocal microscopy zendabuko. [19]. Njengoko zombini i-inhibitory kunye ne-excitatory synapses ziyinxalenye ebalulekileyo yomjikelezo womvuzo wechiza [13], [27], [28] sisebenzise le ndlela yenoveli yokuvavanya utshintsho lwe-morphological kwi-PFC ngexesha lokuyeka i-cocaine. Amashumi asixhenxe amacandelo e-PFC asuka kwi-hemisphere yengqondo ye-5 ye-joked-saline kunye ne-5 yeempuku ezinamava e-cocaine zadyojwa zii-antibodies kwi-PSD95, i-postsynaptic excitatory marker, i-synaptophysin, i-presynaptic marker, kunye ne-GAD65, ebhale i-neurons e-inhibitory kunye ne-synapses. Uxinaniso lwe-Synapse kunye nepesenti ye-synapses ezithintelayo ziye zamiselwa kwi-cortical layer V (Umzobo 1A kunye 1B). Iziphumo zethu zibonisa ukuba ngexesha lokuyeka i-cocaine kuye kwakho ukuncipha okukhulu kwi-synaptophysin density (Umzobo 1C), elinganisa zonke iitheminali zepresynaptic [t(7)=2, p<0.05]. Akukho kuncipha kubalulekileyo kwi-excitatory synapse density [t(8)=0.48, iphe=0.32] njengoko kulinganiswa ngokubala i-PSD95 puncta (Umzobo 1D). Okubangela umdla kukuba, bekukho umkhwa ongabalulekanga wokunyuka kwepesenti ye-GAD65-positive inhibitory synapses [t(8)=-1.39, iphe=0.9] (Umzobo 2E).
Ukuyeka i-cocaine kunciphisa i-dendritic branching ngelixa ukunyusa okwethutyana ukuxinana komnqonqo kwi-PFC.
Indlela yeGolgi yayisetyenziselwa ukuhlola utshintsho kwi-neuronal branching kunye ne-dendritic spine density ukuze kuqinisekiswe utshintsho lwe-ultrastructural olubonwa kwi-synapse density (Umzobo 1). Senze icandelo elinye ngokukhawuleza ukufakwa kwe-Golgi kwi-subset ye-neurons kwi-PFC ukusuka kwezinye ii-hemispheres zezilwanyana ezifanayo ezisetyenziselwa izifundo ze-tomography. I-Dendritic branching, i-dendritic spine counts, kunye ne-spine morphology yavavanywa. Ii-neurons ezimbini ezimele i-pyramidal ezivela kwi-PFC yolawulo lwetyuwa edyokhweni kunye negundane elivezwe yi-cocaine. Umzobo 2A. Isakhiwo seSholl silinganisa inani leendlela zokudityaniswa (iindawo zesebe) phakathi kwezangqa ezinzulu kwirediyo phakathi kwe-5–250 µm. Iziphumo zethu zibonisa ukuba emva kweentsuku ezi-7 zokuyeka ukuzilawula nge-cocaine kuye kwakho ukuncipha okubonakalayo kobunzima be-dendritic (Umzobo 2B). Amanyathelo amabini aphindaphindiweyo Uhlalutyo lwe-ANOVA lwedatha yeploti lubonakalise iziphumo eziphambili zonyango [F(1,738)=30.59, p<0.0001] kunye neradiyasi [F(245, 738)=289.6, p<0.0001] (Umzobo 2B), eqinisekisa ukulahleka kwe-dendrites evumelana nokulahleka kwe-synapses elinganiswe kwizifundo zoluhlu (Umzobo 1C). Uhlalutyo lwesibini kunye neyesithathu i-basilar dendrites ibonise ukonyuka okukhulu kwi-dendritic spines emva kweentsuku ze-7 zokuyeka i-cocaine [t (6)=-3.12, iphe<0.05] (Umzobo 2D). Ngokukodwa, ukuyeka ukubonakaliswa kwe-cocaine kwandisa inani le-spine subtype, ngelixa kungekho mpembelelo ibalulekileyo kwezinye ii-subtypes zomqolo (Umzobo 2E), njengoko kutyhilwe ngeendlela ezimbini iindlela eziphindaphindiweyo ze-ANOVA ezineziphumo eziphambili zonyango [F(1,30)=11.9, iphe=0.0017], uhlobo olusezantsi lomqolo [F(4,30)=57.7, p <0.0001], kunye nonyango olubalulekileyo x ukusebenzisana kwe-spine subtype [F(1, 4, 30)=8.8, p<0.0001].
ingxoxo
Kwesi sifundo sikhoyo sibonisa ukuba kukho utshintsho oluxeliweyo lwesakhiwo kunye ne-synaptic kumaleko we-V we-PFC kulandela iintsuku ezisi-7 zokuyeka ukuzilawula nge-cocaine. Ngokukodwa, kukho ukuhla okubonakalayo kwe-dendritic branching ye-pyramidal neurons kunye nelahleko ngokubanzi kwi-synapse density njengoko kulinganiswe ngokuncipha koxinzelelo lwee-presynaptic boutons ezibhalwe nge-synaptophysin. Ngaphandle kwelahleko yoxinano lwe-presynaptic, i-basal dendrites yomaleko we-V pyramidal neurons iye yanda kakhulu kwi-dendritic spine density, ngakumbi ye-plastic spines. Njengoko singakhange sibone utshintsho olubalulekileyo kubuninzi be-PSD95, kunokucingelwa ukuba kuncipha kwii-terminals ze-presynaptic kodwa ukunyuka koxinzelelo lomqolo kunokuba ngenxa yokwanda kwenani le-multi-synaptic boutons. Ukongeza, kufanelekile ukuba siqaphele ukuba siqwalasele umkhwa wokunyuka kwe-inhibitory synapses kwi-PFC. Ekubeni ama-spines amancinci abandakanyeka kwiplastiki [29], ukwanda kwezi spines kunokubonisa iplastiki yembuyekezo yokugcina igalelo le-synaptic kule neurons edibeneyo elahlekelwe ngamasebe e-dendritic.
Izifundo zangaphambili zibonise ukuba i-cocaine yonyusa i-dendritic arborization kunye noxinzelelo lomqolo kwi-NAc [2]-[4]. Kutshanje, uDumitriu et al., 2012 [30] Ubonise ukuba i-cocaine iguqula ngokuguquguqukayo i-spines proximal kumbindi we-NAc kunye neqokobhe. Ngokukodwa, kwiqokobhe, ukurhoxa kwi-cocaine kwandisa imigca ebhityileyo, ngelixa kuncipha ukuxinana kwentloko ye-mushroom kwiqokobhe le-NAc. [30]. Ngokwahlukileyo kwizifundo ze-NAc, zimbalwa izifundo ezivavanye iziphumo ze-cocaine kwi-neuronal morphology kwi-PFC. [6], [31]. Idatha yethu iyahambelana nophononongo lwamva nje olubonisa ukuba i-cocaine yenza ukonyuka koxinzelelo lomqolo kwi-PFC. [31]. Ngokucacileyo, iimpuku eziye zanokwanda okukhulu kwispines eziqhubekayo nezizinzileyo, oko kukuthi, i-spines ekhoyo kwiintsuku ze-3 emva kokurhoxa, kwi-apical dendrites ibonise amanqaku aphezulu abekwe kwindawo ye-cocaine kunye ne-cocaine-induced hyperactivity. [31]. Uphononongo lwangaphambili kwimpuku ye-PFC umaleko we-II-III neurons wachaza amaxabiso amalunga ne-3 spines nge-µm ye-dendrite kuzo zombini i-apical kunye ne-basal dendrites, inqanaba elixineneyo ngokumangalisayo lespines elinokuguqulwa luxinzelelo. [32]. Amaxabiso ethu ekulawuleni iigundane ze-∼2 spines / 10 µm zamacandelo e-dendritic ziphantsi, ezinokuthi zibe ngenxa ye-neuronal yabantu abahlukeneyo abahlalutywayo (ungqimba lwe-V basal dendrites) okanye umahluko kwindlela yokucinga. Kuphononongo lwangoku sisebenzise icandelo elinye elikhawulezayo lokungcolisa iGolgi ngelixa inaliti ye-iontophoretic yedayi etyheli yeLusifa edityaniswe nemifanekiso yeconfocal yayisetyenziswa nguRadley kunye noogxa. [32] ukujonga i-neuronal kunye ne-dendritic morphology. Ukongeza, iziphumo zethu zikwaqaqambisa ukubaluleka kwexesha lokuzikhwebula kulawulo lwe-cocaine olukhokelela kutshintsho lwengqondo. Ingxelo epapashwe ngaphambili ibonise ukonyuka kwe-dendritic arborization emva kwexesha elide (iintsuku ezingama-24-25) ukurhoxiswa kwi-cocaine kwiimpuku zabasetyhini. [6], ngokungafaniyo nokuncipha kwethu okuphawulweyo emva kweentsuku ze-7 zokuziyeka ngenkani kwiimpuku zamadoda. Ngaphandle kwalo mahluko wendlela kunye nokwahluka kwedatha ye-branching, ukwanda kwenani le-spines kwabonwa kuzo zombini izifundo, eqinisekisa ukuhlengahlengiswa kwesekethe enkulu ngexesha lokuyeka i-cocaine. Uphononongo lwexesha elizayo luya kucacisa ixesha lokuhamba kwezi ziganeko ukuze kuqondwe ukuba ngaba olu tshintsho lwesakhiwo ludlula okanye luhlala ixesha elide.
Iziphumo zethu zibonisa ukuba ukuyeka ngenkani ukuzilawula kwe-cocaine kubangela utshintsho oluguquguqukayo lwesakhiwo kwaye kubangela uhlengahlengiso lwe-synaptic kwi-PFC. Ezi ziphumo zinokuchaza umsebenzi we-hypo-kwi-PFC owenzeka ngenxa yokuvezwa okuphindaphindiweyo kwe-cocaine [8], [33]. Ngaphaya koko, iziphumo zethu zixhasa izifundo zangaphambili ezibonisa ukungasebenzi kwePFC [7], [8], kunye nokwandisa i-GABA ye-extracellular kwi-PFC yangaphakathi ngexesha lokurhoxiswa kwe-cocaine [34]. Ke, iindlela zokubala ze-PFC hypo-umsebenzi emva kokuvezwa okungapheliyo kwe-cocaine [8], [10] inokubandakanya (1) ukwanda kwe-GABAergic, (2) ukunciphisa i-glutamatergic kunye / okanye (3) ukunciphisa igalelo le-dopaminergic synaptic kwi-PFC. Uphononongo lwangoku lubonisa ukuba ukuyeka i-cocaine kunciphisa kakhulu ingxinano ye-synapse njengoko kubonisiwe kukuncipha kwenani le-synaptophysin positive synaptic puncta. Ezi datha zibonisa ukuba kukho ukuncitshiswa kokuphendula kwe-post-synaptic kwi-PFC, enokuthi ixoxwe kukuhla kwe-glutamate okanye igalelo le-dopamine. Ewe, kukho izifundo ezibonisa ukuba i-cocaine yenza ukunciphisa ithoni ye-glutamatergic [35], [36]. Nangona kunjalo, sisebenzisa indlela yeGolgi, siye sabona ukwanda kwenani le-dendritic spines encinci kwi-basal dendrites ye-pyramidal neurons, ebonisa ukwanda kwegalelo elinomdla kwi-PFC ukuya kwi-neurites eseleyo. Ezi datha ziphikisanayo zingabonisa ilahleko iyonke ye-synapses ehambelana nelahleko enkulu ye-dendrites esiyibonayo kunye nempendulo yembuyekezo, mhlawumbi ilamlwe ngokunyuka kwe-BDNF, njengoko kubonisiwe kwiziphumo zethu zangaphambili. [20], ukunyusa ubuninzi be-dendritic spines kwii-neurites ezisele.
Ngokudibeneyo, iziphumo zethu zibonisa uhlengahlengiso oluguqukayo kwi-PFC ngexesha lokuyeka i-cocaine. Ngokukodwa, kukho ukuncipha okubonakalayo kokuqhagamshelwa kwe-synaptic, ilahleko ye-dendritic branching kunye nokwanda kwenani le-spines ezibhityileyo kwi-PFC yegundane kulandela iintsuku ezisi-7 zokuyekwa kweziyobisi ngenkani ekuzilawuleni kwe-cocaine. Ezi ziphumo zinokubonelela ngesiseko sokwakheka komsebenzi oqatshelweyo obonwe kwi-PFC yabaxhaphazi abangapheliyo be-cocaine kwaye mhlawumbi ichaze ukulahleka kolawulo lokuqonda okwenzeka ngexesha lokukhotyokiswa kwe-cocaine.
Imibulelo
Ababhali bangathanda ukubulela uGavin Sangrey ngoncedo lwakhe ngokulungiselela ii-capsules ezifakwe ngaphakathi.
Ingxelo Yenkxaso
Lo msebenzi uxhaswe ngezibonelelo zeNIDA DA22339 kunye DA033641 (RCP & GSV) kunye DA18678 (RCP). I-HDS ixhaswe ngumntu ngamnye we-K01 ibhaso (DA030445). Abaxhasi bemali babengenayo indima ekuyilweni kokufunda, ukuqokelela idatha kunye nohlalutyo, isigqibo sokupapasha, okanye ukulungiswa kombhalo wesandla.
Ucaphulo
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