Comments: Nora Volkow yog lub taub hau ntawm NIDA. Qhov no npog lub luag hauj lwm ntawm dopamine (D2) receptors thiab desensitization hauv kev quav tshuaj.
Pov Tseg Tau Tshaj Xov Xwm Txhaj Tshuaj Tiv Thaiv
Hlwb 4, 2004
Volume 39 Number 11 Nplooj ntawv 32
Jim Rosack
Cov mob muaj yees tuaj yeem yog qhov hloov pauv ntawm "lub ntsuas dej" hauv qhov kev txhawb nqa ib txwm tsis tau lees paub tias yog neeg raug mob, tab sis qhov cuam tshuam ntawm cov tshuaj ntawm kev tsim txom nyob rau hauv lub hlwb dopamine system muaj salient heev, NIDA tus thawj coj ntseeg.
Nora Volkow, MD, tau kawm txog tib neeg lub hlwb cov lus teb rau kev quav yeeb tshuaj rau ze li 25 xyoo. Tam sim no, tom qab tag nrho cov xyoo ntawm kev soj ntsuam thiab kev soj ntsuam, nws tau siv nws txoj haujlwm ua tus thawj coj ntawm National Institute ntawm Kev Tsim Txom (NIDA) los nrhiav cov lus teb rau cov lus nug tseem ceeb: vim li cas tib neeg lub hlwb tau quav tshuaj?
Qhov tseeb tiag, tom qab peb lub hlis dhau los ntawm ib lub xyoo dhau los no xav txog qhov yooj yim lo lus nug, Volkow-siv nws txoj kev tshawb fawb thiab lwm cov neeg tshawb txuj tshawb fawb-tam sim no ntseeg hais tias txoj hauj lwm yog qhov zoo rau nws txoj kev.
Raws li nws qhov kev coj, NIDA-cov kws tshawb nrhiav nyiaj txiag yog nyob rau hauv kub nrhiav cov lus teb. Lub hli tas los, Volkow qhia nws cov kev xav nrog ib pawg neeg coob dhau mus thaum muaj kev qhuab qhia hais txog psychiatrist ntawm APA lub rooj sib tham ib xyoos ib zaug hauv New York City.
Kev tshawb nrhiav lub cev ntev ntev tau pom tias txhua yam tshuaj ntawm kev quav tshuaj muaj zog ua rau dopamine kev ua haujlwm hauv tib neeg lub hlwb limbic. Tab sis, Volkow nyuab siab, "thaum qhov kev nce hauv dopamine no yog qhov tsim nyog los ua kev quav, nws tsis tshua piav txog kev quav tshuaj yeeb quav cawv. Yog tias koj muab tshuaj ntawm kev tsim txom rau ib tus neeg twg, lawv cov koob tshuaj dopamine nce ntxiv. Tiam sis feem coob tsis quav dej quav cawv. ”
Dhau lub xyoo dhau los, cov kev tshawb fawb ntawm lub paj hlwb pom tau hais tias qhov nce hauv dopamine txuam nrog tshuaj yeeb ntawm kev tsim txom tsis tsawg dua cov neeg uas muaj yees tshaj li cov neeg uas tsis muaj kev quav yeeb quav tshuaj. Tsis tas li ntawd, cov neeg tsis muaj zog tiv thaiv kev quav yeeb quav tshuaj, qhov sib npaug me me ntawm qhov kev sib tw ua rau me nyuam ua rau lub siab xav mus nrhiav kev siv yeeb tshuaj ntau dua.
Puas yog dopamine ua lub luag haujlwm rau qhov kev hloov pauv no? ” Volkow nug. Dab tsi ua rau yuam kom siv tshuaj tiv thaiv kev tsim txom? Dab tsi ua rau tus neeg quav yeeb quav tshuaj ploj mus? ”
Kev Sau Npe Nkag Hauv Ib Qee Blanks
Cov kev nce qib hauv cov tswv yim los ntawm lub hlwb tau tso cai rau cov kws tshawb fawb siv cov cim tshuaj biochemical sib txawv los saib cov khoom siv ntawm cov txheej txheem dopamine - lub chaw dopamine hloov chaw thiab dopamine receptors (tsawg kawg plaub qhov sib txawv ntawm dopamine receptors tau txheeb kom paub txog hnub). Tsis tas li ntawd, cov kws tshawb nrhiav tam sim no tuaj yeem saib cov kev hloov pauv hauv lub hlwb cov metabolism hauv lub sijhawm, siv cov cim biochemical rau cov piam thaj, kom pom tias cov tshuaj ntawm kev tsim txom cuam tshuam rau cov metabolism.
Cov kev nce qib no tau tso cai rau peb saib cov tshuaj sib txawv ntawm kev tsim txom thiab seb muaj kev cuam tshuam dab tsi thiab cov kev pauv twg [hauv dopamine system] cuam tshuam nrog lawv li cas, "Volkow piav qhia. "Dab tsi peb yuav tsum paub yog qhov cuam tshuam thiab kev hloov pauv cuam tshuam rau txhua yam tshuaj ntawm kev tsim txom."
”Nws tau pom meej thaum ntxov tias qee cov tshuaj ntawm kev tsim txom tshwm sim cuam tshuam rau dopamine thauj neeg, tab sis lwm tus tsis ua. Kev tshawb nrhiav tom qab ntawd tsom mus rau dopamine receptors thiab metabolism kom pom cov teebmeem tshwm sim, Volkow tau piav qhia. Ib qho ntawm nws txoj kev tshawb fawb thaum 1980s qhia tau zoo ib yam li txo qis hauv dopamine receptor concentration, tshwj xeeb tshaj yog nyob rau hauv ventral striatum, ntawm cov neeg mob quav yeeb dawb, piv nrog kev tswj hwm. Volkow tau mob siab tias pom tias cov kev txo qis no tau ua ntev ntev, zoo dhau ntawm kev daws teeb meem ntawm kev mob thim rov qab los ntawm yeeb dawb.
"Qhov kev txo qis hauv dopamine hom-2 receptors tsis yog tshwj xeeb rau kev quav yeeb dawb xwb", Volkow hais ntxiv. Lwm qhov kev tshawb fawb pom tias muaj cov neeg zoo sib xws los ntawm kev haus cawv, quav yeeb dawb, thiab methamphetamine.
"Yog li, txhais li cas, nws txo qis hauv D2 receptors ntawm kev quav?" Volkow nug.
Kev kho kom zoo rau lub siab
Volkow hais tias "Kuv ib txwm pib nrog cov lus teb yooj yim dua, thiab yog tias lawv tsis ua haujlwm, ces kuv cia kuv lub hlwb hloov siab," ua rau cov neeg nyiam coob.
Tus kab mob dopamine, nws hais tias, nws teb rau cov stimulatory stimulants-rau ib yam dab tsi uas yog ib qho txaus siab, tseem ceeb, los yog muaj nqis txaus siab rau. Lwm yam yuav tuaj yeem ua kom zoo, xws li cov suab paj nruag tshiab lossis kev xav tsis zoo los yog kev ua kom zoo thaum lawv raug hem.
Volkow tau hais tias "Yog li dopamine tab tom hais tiag tiag," Saib seb, mob siab rau qhov no - nws yog qhov tseem ceeb. "Dopamine cim salience."
Tab sis, nws hais ntxiv, dopamine feem ntau nyob rau hauv cov lus sib dhos tsuas yog ib lub sijhawm luv luv - tsawg dua 50 microseconds - ua ntej nws rov siv dua los ntawm dopamine transporter. Yog li nyob rau hauv ib txwm muaj xwm txheej, dopamine receptors yuav tsum muaj txaus thiab rhiab yog tias lawv yuav them sai sai rau kev tawg me ntsis ntawm dopamine uas yog npaj los nqa cov lus, "Ua tib zoo mloog!"
Nrog rau D2 tus neeg tuaj yeem txuam nrog kev tiv thaiv, tus neeg muaj lub siab tsis tshua muaj tus cwj pwm tsis hnov mob ua rau nws ua rau nws coj tus cwj pwm coj.
"Feem ntau cov tshuaj ntawm kev tsim txom, txawm li cas los xij," Volkow tau hais tias, "thaiv cov dopamine thauj hauv lub hlwb nqi zog kev sib tw, tso cai rau cov neurotransmitter nyob hauv cov teeb meem no mus piv rau lub neej nyob mus ib txhis. Qhov no ua rau muaj txiaj ntsig loj thiab kav ntev, txawm hais tias tus neeg ntawd tau txo qis cov txais.
"Thaum lub sijhawm dhau los, cov neeg quav tau kawm paub tias cov kev tawm dag zog tsis dhau mus," Volkow hais txog qhov teebmeem. "Tab sis cov tshuaj ntawm kev tsim txom yog."
Yog li ntawd, tus poj niam nws nug ntxiv tias, "Ua li cas peb thiaj paub hais tias yog qaib thiab yog lub qe?" Puas yog kev siv tshuaj txuas ntxiv kev tsim txom ua rau txo qis hauv D2 cov neeg txais, lossis puas yog cov neeg siv tshuaj tsawg dua ua rau kev quav tshuaj?
Kev tshawb nrhiav yog tam sim no hais qhov lus nug ntawd, Volkow paub tseeb. Thiab nws pom tias tom kawg yuav yog cov lus teb. Hauv cov neeg tsis tau txiav txim siab uas tsis tau raug cov tshuaj lom neeg raug tsim txom, muaj ntau yam ntawm D2 receptor concentrations. Qee cov kev tswj kev qov meej muaj D2 qib kom qis qis dua li qee cov yeeb yaj kiab.
Nyob rau hauv ib txoj kev tshawb nrhiav, Volkow tau hais tias, cov neeg tshawb nrhiav tau muab cov tshuaj methylphenidate mus rau cov neeg tsis muaj kev quav yeeb quav tshuaj thiab thov kom lawv ntsuas seb cov tshuaj ua rau lawv xav li cas.
"Cov neeg uas muaj D2 receptors siab hais tias nws txaus ntshai heev, thiab cov neeg uas muaj D2 receptors qib qis dua yuav hais tau tias nws ua rau lawv zoo," Volkow tau tshaj tawm.
"Tam sim no," nws hais ntxiv, "qhov no tsis txhais tau tias cov tib neeg uas muaj qib qis ntawm D2 receptors yog qhov yooj yim quav tshuaj. Tab sis nws yuav txhais tau tias cov tib neeg uas muaj D2 siab txais ntau kawg yog muaj qhov lus teb hnyav heev rau qhov tshwm sim ntau dua ntawm dopamine pom nyob rau hauv cov tshuaj ntawm kev tsim txom. Cov kev paub yog inherently aversive, muaj feem tiv thaiv lawv los ntawm kev quav. "
Hauv txoj kev xav, nws hais tias, yog tias cov neeg tshawb nrhiav kev quav yeeb quav tshuaj tuaj yeem nrhiav txoj hauv kev ua kom muaj qhov nce ntawm D2 receptors hauv lub hlwb, "koj tuaj yeem hloov pauv cov neeg uas muaj D2 qis dua thiab tsim kev coj cwj pwm tsis zoo rau cov tshuaj ntawm kev tsim txom."
Cov kev tshawb pom tsis ntev los no los ntawm ib qho ntawm Volkow qhov kev tshawb fawb tom qab kev tshawb fawb pom tau tias nws muaj peev xwm hauv cov nas los qhia rau hauv lub hlwb adenovirus nrog lub noob rau D2 receptor ntau lawm, ua rau muaj kev nce hauv D2 receptor ntau. Hauv kev teb, cov nas sib txuas lus txo qis lawv tus kheej kom tsawg los ntawm kev haus cawv. Lwm cov kws tshawb nrhiav tshiab nyuam qhuav rov ua dua cov kev tshawb pom nrog yeeb thiab.
"Tab sis,", Volkow hais tias, "koj xav tau ntau tshaj qhov tsawg ntawm D2 receptors." Kev soj ntsuam ntawm cov metabolism hauv qabzib tau qhia tias cov metabolism hauv lub cev qis dua qhov tseem ceeb hauv orbital frontal cortex (OFC) thiab cingulate gyrus (CG) hauv kev teb rau cocaine, haus dej cawv, methamphetamine, thiab tshuaj maj hauv cov neeg quav, piv nrog kev tswj hwm. Thiab, nws tau ntxiv, qhov kev txo qis hauv cov metabolism tseem cuam tshuam txog kev txo qis ntawm D2 receptors.
Volkow tau tshaj tawm tias qhov ua tsis ua haujlwm nyob rau hauv OFC thiab CG "ua rau cov tib neeg tsis tuaj yeem txiav txim siab txog kev txiav txim siab ntawm qhov kev siv yeeb tshuaj - lawv noj cov tshuaj ntawm kev tsim txom, tsis tas li nws tsis ua rau lawv muaj kev lom zem thiab, feem ntau, muaj qhov tsis zoo. ” Txawm li cas los tseem, lawv tsis tuaj yeem tso tseg tsis siv tshuaj.
Lwm cov kev tshawb fawb tau qhia tias kev tswj tsis pub lwm tus; nqi zog, kev txhawb, thiab tsav; thiab kev kawm thiab cim xeeb circuits yog txhua yam txawv txav rau cov tib neeg uas muaj kev nyuab siab, nws tau sau tseg. Vim li ntawd, kev tiv thaiv kev quav tshuaj yuav tsum muaj kev sib xyuas, kev ua haujlwm.
Volkow xaus lus tias "Tsis muaj leej twg xaiv kev quav yeeb quav tshuaj." "Lawv tsuas yog muaj peev xwm tsis muaj peev xwm xaiv tsis mus quav yeeb quav tshuaj."
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