Inhibition txheej txheem nyob rau hauv lub hauv paus paj hlwb (CNS) tau nthuav tawm raws li kev tshawb pom rov qab rau xyoo 1962 los ntawm IM Sechenov. Tus kws tshawb fawb pom qhov tshwm sim no thaum kawm txog qhov khoov reflexes ntawm Qav, qhov excitation uas tau tswj los ntawm cov tshuaj lom neeg ntawm stimulation nyob rau hauv nruab nrab cheeb tsam ntawm lub hlwb. Txog niaj hnub no, nws tau lees paub tias qhov kev coj cwj pwm ntawm lub paj hlwb yog qhov tseem ceeb rau kev tiv thaiv kev tiv thaiv ntawm lub cev. Nyob rau tib lub sijhawm, cov kws tshawb fawb niaj hnub txheeb xyuas cov theem sib txawv thiab cov yam ntxwv ntawm cov txheej txheem no. Kev saib xyuas tshwj xeeb yog them rau presynaptic thiab pessimal inhibitions, uas cuam tshuam rau kev sib koom tes ntawm reflexes thiab kev ua haujlwm ntawm kev tiv thaiv hauv cov hlab ntsha hauv ntau txoj kev.
Cov txheej txheem ntawm inhibition hauv CNS raws li kev tshuaj xyuas biochemical
Synapses lub luag haujlwm rau kev tswj hwm kev zoo siab thiab kev khaus khaus, feem ntau ua haujlwm nrog cov tshuaj chloride, qhib lawv. Tawm tsam keeb kwm yav dhau los ntawm cov tshuaj tiv thaiv no, cov ions tuaj yeem dhau los ntawm cov kab mob neuronal. Hauv cov txheej txheem no, nws yog ib qho tseem ceeb kom nkag siab qhov tseem ceeb ntawm Nernst muaj peev xwm rau ions. Nws yog sib npaug rau -70 mV, thaum tus nqi ntawm lub membrane neuron nyob rau hauv lub siab lub ntsws kuj tsis zoo, tab sis nws twb sib raug mus rau -65 mV. Qhov sib txawv no ua rauqhib cov channel los xyuas kom meej qhov kev txav ntawm cov ions tsis zoo los ntawm cov kua dej ntxiv.
Thaum lub sijhawm cov tshuaj tiv thaiv no, lub peev xwm ntawm daim nyias nyias kuj hloov pauv. Piv txwv li, nws tuaj yeem nce mus rau -70 mV. Tab sis kuj qhib cov poov tshuaj raws tuaj yeem provoke pessimal inhibition. Physiology nrog cov txheej txheem ntawm kev tswj ntawm excitation nyob rau hauv cov ntaub ntawv no yuav qhia nyob rau hauv lub zog ntawm zoo ions sab nraum. Lawv maj mam nce lawv lub peev xwm tsis zoo thaum lawv poob lawv txoj kev thaj yeeb. Yog li ntawd, ob qho tib si txheej txheem ua rau muaj kev nce hauv qhov tsis zoo, uas ua rau muaj kev ntxhov siab. Lwm qhov yog tias yav tom ntej cov nqi them tuaj yeem tswj hwm los ntawm cov neeg thib peb cov txheej txheem tswj hwm, vim qhov tshwj xeeb, cov txiaj ntsig ntawm kev tso tseg cov nthwv dej tshiab ntawm excitation ntawm paj hlwb qee zaum tshwm sim.
Presynaptic inhibitory txheej txheem
Cov tshuaj tiv thaiv zoo li no provoke inhibition ntawm paj hlwb impulses hauv axonal xaus. Qhov tseeb, qhov chaw ntawm lawv keeb kwm txiav txim siab lub npe ntawm hom kev txwv no - lawv ua ntej cov channel cuam tshuam nrog synapses. Nws yog cov ntsiab lus axonal uas ua raws li qhov txuas nquag. Ib tug txawv teb chaws axon xa mus rau lub excitatory cell, tso ib tug inhibitory neurotransmitter. Qhov kawg cuam tshuam rau postsynaptic membrane, provoking depolarization txheej txheem hauv nws. Yog li ntawd, cov tswv yim los ntawm cov synaptic cleft tob rau hauv lub excitatory axon yog inhibited, tso tawm ntawm cov neurotransmitter txo qis thiab lub sij hawm luv luv ntawm cov tshuaj tiv thaiv tshwm sim.
Tsuas yog nyob rau theem no, qee zaum muaj kev cuam tshuam tsis zoo,uas tuaj yeem pom dua. Nws tsim nyob rau hauv cov xwm txheej uas cov txheej txheem tseem ceeb ntawm excitation tiv thaiv keeb kwm yav dhau ntawm muaj zog depolarization tsis nres nyob rau hauv kev cuam tshuam ntawm ntau yam impulses. Raws li kev ua tiav ntawm cov tshuaj tiv thaiv presynaptic, nws nce mus txog qhov siab tshaj plaws tom qab 15-20 ms thiab kav ntev txog 150 ms. Qhov thaiv ntawm qhov inhibition yog muab los ntawm convulsive tshuaj lom - picrotoxin thiab biculin, uas tawm tsam axon mediators.
Kev txheeb xyuas hauv cheeb tsam hauv CNS kuj tseem yuav txawv. Raws li txoj cai, cov txheej txheem presynaptic tshwm sim nyob rau hauv tus txha caj qaum thiab lwm yam qauv ntawm lub hlwb qia. Ib qho kev phiv ntawm cov tshuaj tiv thaiv tej zaum yuav yog ib qho kev nce hauv synaptic vesicles, uas yog tso tawm los ntawm neurotransmitters nyob rau hauv lub excitatory ib puag ncig.
Hom ntawm cov txheej txheem presynaptic inhibition
Raws li txoj cai, lateral thiab thim rov qab cov tshuaj tiv thaiv ntawm hom no yog qhov txawv. Tsis tas li ntawd, lub koom haum ntawm cov txheej txheem ntawm ob qho tib si cov txheej txheem feem ntau converges nrog postsynaptic inhibition. Lawv qhov txawv txav yog vim qhov tseeb tias qhov kev zoo siab nres tsis yog ntawm cov neuron nws tus kheej, tab sis ntawm txoj hauv kev rau nws lub cev. Thaum lub sij hawm lateral inhibition, cov tshuaj tiv thaiv kab mob tshwm sim los ntawm kev cuam tshuam tsis tau tsuas yog rau lub hom phiaj neurons, uas cuam tshuam los ntawm excitation, tab sis kuj nyob ze cov hlwb, uas tej zaum yuav pib qaug zog thiab tsis o. Cov txheej txheem no yog hu ua lateral vim hais tias qhov chaw ntawm excitation yog localized nyob rau hauv lub lateral seem txheeb ze rau cov neuron. Cov xwm txheej zoo sib xws tshwm sim hauv cov tshuab hnov lus.
Raws li cov kev cuam tshuam ntawm hom rov qab, lawv qhov piv txwv yog qhov tshwj xeeb tshaj yog pom ntawm kev coj tus cwj pwmpaj hlwb los ntawm qhov chaw ntawm impulses. Hauv qee txoj kev, qhov kev tawm tsam ntawm qhov tshuaj tiv thaiv no tuaj yeem hu ua pessimal inhibition. Lub physiology ntawm lub hauv nruab nrab lub paj hlwb nyob rau hauv cov ntaub ntawv no txiav txim lub dependence ntawm tus yam ntxwv ntawm lub ndlwg ntawm excitation tsis ntau npaum li cas ntawm qhov chaw raws li nyob rau hauv lub zaus ntawm stimuli. Rov qab inhibition xav tias axon mediators yuav raug coj mus rau lub hom phiaj neurons los ntawm ntau txoj hauv kev ntawm collaterals. Cov txheej txheem no yog siv los ntawm lub hauv paus ntsiab lus ntawm kev tawm tswv yim tsis zoo. Ntau tus kws tshawb fawb tau sau tseg tias nws yuav tsum tau ua rau muaj peev xwm tswj hwm tus kheej ntawm excitation ntawm neurons nrog kev tiv thaiv ntawm convulsive tshua.
Pessimal braking mechanism
Yog tias cov txheej txheem presynaptic tau tham saum toj no tau txiav txim siab los ntawm kev sib cuam tshuam ntawm tus kheej lub hlwb nrog lwm qhov chaw ntawm kev khaus, ces qhov no qhov tseem ceeb yuav yog cov lus teb ntawm neurons rau excitations. Piv txwv li, nrog kev ua kom nrawm nrawm, cov leeg nqaij tuaj yeem teb nrog qhov nce ntawm qhov khaus. Cov txheej txheem no tseem hu ua Vvedensky's pessimal inhibition tom qab tus kws tshawb fawb uas tshawb pom thiab tsim lub hauv paus ntsiab lus ntawm kev sib cuam tshuam ntawm paj hlwb.
Pib nrog, nws yog ib qho tsim nyog hais tias txhua lub paj hlwb muaj nws tus kheej qhov zoo tshaj plaws excitation pib, stimulated los ntawm stimulation ntawm ib tug tej zaus. Raws li lub suab ntawm cov impulses tsim, tetanic contraction ntawm cov leeg yuav nce. Tsis tas li ntawd, kuj tseem muaj theem ntawm kev nce ntau zaus uas cov hlab ntsha yuav tsum tsis txhob khaus thiab nkag mus rau theem so, txawm tias txuas ntxiv mus.cov txheej txheem zoo siab. Tib yam tshwm sim thaum qhov kev siv zog ntawm kev ua ntawm cov neeg kho kom haum xeeb txo qis. Nws tuaj yeem hais tau tias qhov no yog qhov rov qab tsim dua tshiab ntawm pessimal inhibition. Lub physiology ntawm synapses nyob rau hauv cov ntsiab lus no yuav tsum tau txiav txim siab raws li tus yam ntxwv ntawm lability. Hauv synapses, qhov ntsuas no qis dua hauv cov leeg nqaij. Qhov no yog vim lub fact tias kev txhais lus ntawm excitation yog txiav txim los ntawm cov txheej txheem ntawm kev tso tawm thiab ntxiv splitting ntawm tus neeg nruab nrab. Ntxiv dua thiab, nyob ntawm tus cwj pwm ntawm ib lub cev, cov kev cuam tshuam no tuaj yeem tshwm sim ntawm tus nqi sib txawv.
Qhov zoo tshaj plaws thiab pessimum yog dab tsi?
Txoj kev hloov pauv ntawm lub xeev excitation mus rau inhibition yog cuam tshuam los ntawm ntau yam, feem ntau muaj feem xyuam nrog cov yam ntxwv ntawm kev txhawb nqa, nws lub zog thiab zaus. Qhov pib ntawm txhua nthwv dej tuaj yeem hloov pauv qhov tsis muaj lability, thiab qhov kev kho no kuj tau txiav txim los ntawm lub xeev tam sim no ntawm tes. Piv txwv li, pessimal inhibition tuaj yeem tshwm sim thaum cov leeg nyob hauv qhov kev tsa siab lossis theem refractory. Ob lub xeev no yog txhais los ntawm cov ntsiab lus ntawm qhov zoo tshaj plaws thiab pessimum. Raws li rau thawj, nyob rau hauv cov ntaub ntawv no, cov yam ntxwv ntawm lub impulses sib haum mus rau qhov taw qhia ntawm cell lability. Nyob rau hauv lem, lub pessimum qhia tias lability ntawm cov hlab ntsha yuav qis dua cov nqaij fibers.
Nyob rau hauv cov ntaub ntawv ntawm pessimum, qhov tshwm sim ntawm qhov cuam tshuam ntawm kev khaus yav dhau los yuav yog qhov txo qis lossis ua tiav kev thaiv ntawm kev hloov pauv ntawm excitatory nthwv dej los ntawm cov hlab ntsha mus rau cov leeg. Yog li ntawd, tetanus yuav tsis tuaj thiab pessimal inhibition yuav tshwm sim. Qhov zoo tshaj plaws thiab pessimum hauv qhov noCov ntsiab lus sib txawv ntawm qhov sib txawv ntawm qhov kev txhawb nqa tib yam, tus cwj pwm ntawm cov leeg yuav raug nthuav tawm hauv kev cog lus lossis so.
Los ntawm txoj kev, qhov zoo tshaj plaws lub zog tsuas yog hu ua qhov siab tshaj plaws contraction ntawm fibers ntawm qhov zoo tshaj plaws zaus ntawm excitatory signals. Txawm li cas los xij, kev txhim kho thiab txawm tias ob npaug ntawm qhov cuam tshuam yuav tsis ua rau muaj kev sib txuas ntxiv, tab sis ntawm qhov tsis sib xws, nws yuav txo qis qhov kev siv zog thiab, tom qab ib ntus, yuav coj cov leeg mus rau hauv lub xeev ntawm kev thaj yeeb. Txawm li cas los xij, muaj qhov cuam tshuam kev ua rau muaj kev ntxhov siab yam tsis muaj kev cuam tshuam neurotransmitters.
Txhob Cia Siab thiab Tsis Muaj Kev Tiv Thaiv
Rau kev nkag siab ntau ntxiv ntawm cov lus teb rau stimuli, nws tsim nyog xav txog ob hom kev cuam tshuam. Nyob rau hauv cov ntaub ntawv ntawm ib tug conditioned teb, nws yog xav tias reflex yuav tshwm sim nrog me me los yog tsis muaj zog ntxiv los ntawm unconditioned stimuli.
Cais, nws tsim nyog xav txog qhov sib txawv ntawm cov tshuaj tiv thaiv kab mob, uas yuav muaj kev tso tawm ntawm qhov kev txhawb nqa muaj txiaj ntsig zoo rau lub cev. Qhov kev xaiv ntawm qhov zoo tshaj plaws ntawm excitation yog txiav txim los ntawm yav dhau los kev ntawm kev sib raug zoo nrog paub stimuli. Yog tias lawv hloov pauv ntawm qhov kev ua tau zoo, tom qab ntawd cov tshuaj tiv thaiv reflex tseem yuav tso tseg lawv txoj haujlwm. Ntawm qhov tod tes, unconditional pessimal inhibition yuav tsum tau cov hlwb kom hnov mob tam sim ntawd thiab unambiguously rau stimuli. Txawm li cas los xij, nyob rau hauv cov xwm txheej ntawm kev mob siab thiab tsis tu ncua los ntawm tib qhov kev txhawb nqa, cov kev taw qhia reflex txo qis thiab los ntawmlub sij hawm, yuav tsis muaj kev cuam tshuam braking.
Kev zam yog qhov kev txhawb nqa uas muaj cov ntaub ntawv tseem ceeb ntawm kev lom neeg. Nyob rau hauv cov ntaub ntawv no, cov reflexes tseem yuav muab cov lus teb.
Qhov tseem ceeb ntawm cov txheej txheem braking
Lub luag haujlwm tseem ceeb ntawm cov txheej txheem no yog txhawm rau ua kom muaj kev sib txuas thiab kev tshuaj xyuas cov paj hlwb hauv CNS. Tom qab ua tiav cov teeb liab, cov haujlwm ntawm lub cev tau sib koom ua ke, ob leeg ntawm lawv tus kheej thiab nrog rau ib puag ncig sab nraud. Yog li, cov txiaj ntsig ntawm kev sib koom tes yog tiav, tab sis qhov no tsis yog tib txoj haujlwm ntawm kev sib tsoo. Yog li, kev ruaj ntseg lossis kev tiv thaiv lub luag haujlwm tseem ceeb heev. Nws tuaj yeem raug nthuav tawm hauv kev nyuaj siab ntawm lub hauv paus paj hlwb los ntawm afferent insignificant signals tawm tsam keeb kwm ntawm pessimal inhibition. Cov txheej txheem thiab qhov tseem ceeb ntawm cov txheej txheem no tuaj yeem nthuav tawm hauv kev sib koom ua haujlwm ntawm cov chaw tawm tsam uas tsis suav nrog cov txiaj ntsig tsis zoo.
Rov qab inhibition, nyob rau hauv lem, tuaj yeem txwv qhov zaus ntawm motoneuron impulses nyob rau hauv qaum qaum, ua ob qho tib si tiv thaiv thiab kev sib koom tes. Nyob rau hauv ib rooj plaub, lub cev muaj zog neuron impulses yog koom tes nrog tus nqi ntawm contraction ntawm cov leeg innervated, thiab nyob rau hauv lwm yam lus, overexcitation ntawm paj hlwb yog tiv thaiv.
Qhov tseem ceeb ntawm cov txheej txheem presynaptic
Ua ntej ntawm tag nrho cov, nws yuav tsum tau hais tias cov yam ntxwv ntawm synapses tsis tas li, yog li ntawd, qhov tshwm sim ntawm inhibition tsis tuaj yeem suav tias yog kev zam. Nyob ntawm cov xwm txheej, lawv txoj haujlwm tuaj yeem ua nrog ib lossis lwm qhovdegree ntawm kev ua si. Nyob rau hauv qhov zoo tshaj plaws lub xeev, qhov tshwm sim ntawm pessimal inhibition yuav muaj kev nce nyob rau hauv lub zaus ntawm irritating impulses, tab sis, raws li kev soj ntsuam ntawm lub zog ntawm yav dhau los cov cim qhia, ib tug nce nyob rau hauv kev siv kuj yuav ua rau kom so ntawm cov nqaij fibers. Tag nrho cov no qhia txog qhov tsis ruaj khov ntawm kev ua haujlwm tseem ceeb ntawm cov txheej txheem ntawm inhibition ntawm lub cev, tab sis lawv, nyob ntawm cov xwm txheej, tuaj yeem qhia tau tshwj xeeb.
Piv txwv li, ntawm qhov muaj zog ntawm kev txhawb siab, kev ua haujlwm ntev ntev ntawm kev sib cuam tshuam ntawm cov neurons tuaj yeem pom. Qhov no yog li cas lub functionality ntawm presynaptic fiber ntau thiab, tshwj xeeb tshaj yog, nws hyperpolarization tuaj yeem tshwm sim nws tus kheej. Ntawm qhov tod tes, cov cim qhia ntawm kev nyuaj siab tom qab ua haujlwm kuj tshwm sim nyob rau hauv lub synaptic apparatus, uas yuav qhia nyob rau hauv ib tug txo nyob rau hauv lub amplitude ntawm lub peev xwm excitatory. Qhov tshwm sim no tuaj yeem tshwm sim hauv synapses thaum lub sij hawm pessimal inhibition tiv thaiv keeb kwm yav dhau los ntawm kev nce siab rau qhov kev txiav txim ntawm neurotransmitter. Qhov no yog li cas cov nyhuv ntawm membrane desensitization yog manifested. Lub plasticity ntawm cov txheej txheem synaptic raws li cov cuab yeej ua haujlwm tseem tuaj yeem txiav txim siab tsim cov kev sib txuas ntawm neural hauv CNS, nrog rau lawv cov kev txhawb zog. Cov txheej txheem no muaj txiaj ntsig zoo rau cov txheej txheem ntawm kev kawm thiab kev txhim kho kev nco.
Txoj kev ntawm postsynaptic inhibition
Cov txheej txheem no tshwm sim nyob rau theem thaum cov neurotransmitter raug tso tawm los ntawm cov saw hlau, uas tau nthuav tawm raws li kev txo qis ntawm cov paj hlwb ntawm cov paj hlwb. Raws li cov kws tshawb fawb, hom kev txwv notshwm sim tawm tsam keeb kwm ntawm thawj hyperpolarization ntawm neuron membrane. Cov tshuaj tiv thaiv no provokes nce permeability ntawm postsynaptic membrane. Nyob rau hauv lub neej yav tom ntej, hyperpolarization cuam tshuam rau lub peev xwm ntawm daim nyias nyias, coj nws mus rau ib qho kev sib npaug ntawm lub xeev - uas yog, theem tseem ceeb ntawm excitability txo. Nyob rau tib lub sijhawm, peb tuaj yeem tham txog kev hloov pauv hloov pauv hauv cov chains ntawm post- thiab presynaptic inhibition.
Cov tshuaj tiv thaiv pessimal nyob rau hauv ib daim ntawv los yog lwm yam tej zaum yuav tshwm sim nyob rau hauv ob qho tib si txheej txheem, tab sis lawv muaj ntau tus yam ntxwv los ntawm cov theem ob ntawm irritation. Nyob rau hauv lem, postsynaptic mechanisms tsim maj mam thiab tsis tawm refractoriness. Qhov no twb yog theem kawg ntawm inhibition, txawm hais tias cov txheej txheem ntawm kev rov qab nce ntxiv hauv excitability kuj tuaj yeem tshwm sim yog tias muaj kev cuam tshuam ntawm kev txhawb nqa ntxiv. Raws li txoj cai, kev nrhiav tau ntawm thawj lub xeev ntawm cov neurons thiab cov leeg nqaij fibers tshwm sim nrog rau kev txo cov nqi tsis zoo.
Zoo kawg
Inhibition yog txheej txheem tshwj xeeb hauv lub hauv paus paj hlwb, ze ze rau cov yam ntxwv ntawm kev khaus thiab excitation. Nrog rau tag nrho cov kev ua ub no ntawm kev sib cuam tshuam ntawm neurons, impulses thiab nqaij fibers, xws li cov tshuaj tiv thaiv yog heev natural thiab zoo rau lub cev. Tshwj xeeb, cov kws tshaj lij taw qhia txog qhov tseem ceeb ntawm kev txwv tsis pub rau tib neeg thiab tsiaj txhu raws li kev tswj hwm kev zoo siab, kev sib koom tes, thiab ua haujlwm tiv thaiv. Cov txheej txheem nws tus kheej yog heev complex thiab multifaceted. Cov kev piav qhia ntawm cov tshuaj tiv thaiv tsim nws lub hauv paus, thiab qhov xwm txheej ntawm kev sib cuam tshuam ntawm cov neeg koomtxiav txim los ntawm cov hauv paus ntsiab lus ntawm pessimal inhibition.
Lub physiology ntawm cov txheej txheem zoo li no tau txiav txim siab tsis yog los ntawm cov qauv ntawm lub hauv paus paj hlwb, tab sis kuj los ntawm kev sib cuam tshuam ntawm cov hlwb nrog lwm yam. Piv txwv li, nyob ntawm qhov inhibitory mediator, lub kaw lus tuaj yeem muab cov lus teb sib txawv, thiab qee zaum nrog tus nqi sib txawv. Nws yog vim qhov no tias qhov sib npaug ntawm kev sib cuam tshuam ntawm cov neurons thiab cov leeg nqaij reflexes yog guaranteed.
Kev kawm nyob rau hauv qhov kev taw qhia no tseem tawm ntau cov lus nug, nrog rau kev ua haujlwm ntawm tib neeg lub hlwb. Tab sis niaj hnub no nws yog pom tseeb hais tias cov mechanisms ntawm inhibition yog ib qho tseem ceeb functional tivthaiv nyob rau hauv kev ua hauj lwm ntawm lub hauv paus paj hlwb. Txaus nws hais tias tsis muaj kev tswj hwm ntuj ntawm lub zog reflex, lub cev yuav tsis tuaj yeem tiv thaiv nws tus kheej los ntawm ib puag ncig, nyob ze rau nws.
