Cholinergic synapses: qauv, muaj nuj nqi

Cholinergic synapses yog qhov chaw nyob rau hauv uas muaj yog hu ntawm ob neurons los yog neuronal hlwb thiab effector txais lub teeb liab. Lub synapse yog muaj li ntawm ob week - presynaptic thiab postsynaptic, raws li zoo raws li los ntawm cov synaptic cleft. Kis ntawm cov hlab impulses yog nqa tawm los ntawm txoj kev ib tug neeg tuaj daws kho, i.e. ib transmitter substance. Qhov no tshwm sim los ntawm tus sis ntawm cov receptor thiab neurotransmitter rau postsynaptic membrane. Qhov no yog lub ntsiab muaj nuj nqi ntawm cholinergic synapses.

Cov Neeg Nruab Nrab thiab receptors

Lub NA parasympathetic neurotransmitter yog acetylcholine receptors - ob hom ntawm cholinergic receptors: H (nicotine) thiab M (muscarine). M-cholinomimetics muaj ib tug ncaj qha kev txiav txim hom yuav hnia receptors nyob rau hauv lub postsynaptic membrane hom.

Synthesis of acetylcholine yog nqa nyob rau hauv lub cytoplasm ntawm cholinergic neuronal txoj. Nws yog tsim nyob rau ntawm choline thiab atsetilkoenzima-A, uas muaj ib tug mitochondrial keeb kwm. Synthesis tshwm sim nyob rau hauv qhov kev txiav txim ntawm lub cytoplasmic enzyme choline. Lub synaptic hlwv tshwm sim deposition ntawm acetylcholine. Nyob rau hauv txhua tus ntawm cov npuas kuj yuav mus txog ob peb txhiab molecules ntawm acetylcholine. Lub paj impulse nkoos qhov kev tso tawm ntawm acetylcholine nyob rau hauv lub synaptic cleft molecules. Tom qab ntawd, nws nkag mus rau rau hauv kev sis raug zoo nrog acetylcholine receptors. Tus qauv ntawm lub cholinergic synapse cim.

qauv

Raws li cov ntaub ntawv, uas muaj nyob rau biochemists, acetylcholine receptor neuromuscular synapse tej zaum yuav muaj tsib protein subunits uas puag ncig lub ion channel thiab cuag los ntawm tag nrho cov thickness ntawm daim nyias nyias uas muaj ib tug lipid. Khub ntawm acetylcholine molecules nrog ib tug khub ntawm α-subunits. Qhov no ua rau lub fact tias yuav qhib lub ion channel thiab cov postsynaptic membrane yog depolarized.

Hom ntawm cholinergic synapses

Cholinergic receptors yog laus nyob rau hauv ntau txoj kev thiab cov tib nyob rau hauv ntau txoj kev uas sensitive rau cov teebmeem ntawm pharmacological cov neeg ua hauj. Nyob rau hauv raws li cov txim hluav taws xob:

• Maskarinochuvstvitelnye cholinergic receptors - thiaj li hu ua M-cholinergic receptors. Yog ib tug alkaloid muscarine xam qhovkev tooj lom mushroom, amanita piv txwv li.
• Nikotinochuvstvitelnye holinoretseptora - qhov thiaj li hu ua H-cholinergic receptors. Nicotine yog ib qho alkaloid pom nyob rau hauv luam yeeb nplooj.

lawv qhov chaw nyob

Tus thawj nyob rau hauv lub postsynaptic cell daim nyias nyias muaj li ntawm effector kabmob. Lawv nyob hauv lub xaus ntawm postganglionic parasympathetic fibers. Nyob rau hauv tas li ntawd, lawv kuj muaj nyob rau hauv neural hlwb, autonomic ganglia thiab nyob rau hauv lub cerebral cortex. Nws twb pom hais tias cov M-cholinergic receptors ntawm txawv localization yog ua kev, uas ua rau yus mus rau ib tug sib txawv rhiab heev rau lub substance ntawm cholinergic synapses pharmacological xwm.

Hom nyob rau hauv lub qhov chaw

Biochemists ob peb hom M-cholinergic receptors:

• Nyob rau hauv autonomic ganglia thiab lub hauv paus poob siab system. Ib tug feature ntawm thawj yog hais tias lawv muaj nyob rau sab nraum ntawm synapses - M1-cholinergic receptors.
• Nyob rau hauv lub plawv. Ib txhia ntawm lawv pab txo tau cov kev tso tawm ntawm acetylcholine - M2-cholinergic receptors.
• Nyob rau hauv lub du nqaij, thiab nyob rau hauv feem ntau ntawm cov endocrine qog - lub M3-cholinergic receptors.
• Nyob rau hauv lub plawv, nyob rau hauv lub phab ntsa ntawm lub pulmonary alveoli, nyob rau hauv lub Cns - M4-cholinergic receptors.
• Muab tso rau hauv lub Cns, nyob rau hauv lub iris ntawm lub qhov muag, muaj qaub ncaug, nyob rau hauv mononuclear ntshav - M5-cholinergic receptors.

Tej yam nyob rau hauv lub cholinergic receptors

Feem ntau ntawm cov teebmeem yog muab los ntawm lub npe hu pharmacological tshuaj rau cov M-cholinergic receptors, vim tus sis ntawm cov tshuaj thiab postsynaptic M2 thiab M3 cholinergic receptors.

Xav txog cov kev faib ntawm cov nyiaj uas kov cholinergic synapses hauv qab no.

H-cholinergic receptors nyob rau hauv daim nyias nyias ntawm lub postsynaptic neurons nyob rau hauv ganglia xaus ntawm txhua preganglionic fibers (nyob rau hauv parasympathetic thiab khuv xim ganglia), nyob rau hauv lub cheeb tsam ntawm lub carotid qhov ntswg, nyob rau hauv lub adrenal medulla, nyob rau hauv neurohypophysis, nyob rau hauv Renshaw hlwb nyob rau hauv skeletal leeg. Lub rhiab heev ntawm qhov sib txawv H-cholinergic receptors txawv rau tshuaj. Piv txwv li, H-cholinergic receptors nyob rau hauv lub autonomic ganglia lug (nruab nrab hom receptors) muaj teeb meem loj sib txawv los ntawm lub H-cholinergic receptors nyob rau hauv skeletal leeg (nqaij hom receptors). Nws yog qhov no feature tso cai rau lawv mus xyua thaiv ganglia tshwj xeeb tshuaj. Piv txwv li, kurarepodnye tshuaj uas muaj peev xwm ntawm thaiv cov hlab neuromuscular kis tau tus mob.

Presynaptic cholinergic receptors thiab adrenoceptors yog muab kev koom tes nyob rau hauv cov kev cai txheej txheem ntawm acetylcholine tso tawm nyob rau synapse neuroeffector xwm. Stimulation ntawm cov receptors yuav inhibit qhov kev tso tawm ntawm acetylcholine.

Acetylcholine reacts nrog H-acetylcholine receptors thiab hloov lawv conformation, tsub kom txog qib ntawm permeability ntawm lub postsynaptic membrane. Acetylcholine muaj ib tug stimulating nyhuv on lub sodium ions, uas ces txeem mus rau hauv lub cell, thiab qhov no ua rau lub fact tias cov postsynaptic membrane yog depolarized. Chiv muaj ib lub zos synaptic muaj peev xwm ua nce mus txog ib tug tej yam muaj nuj nqis, thiab pib cov txheej txheem ntawm generating qhov kev txiav txim zaum. Tom qab hais tias, lub zos zoo siab, uas yog tas rau synaptic cheeb tsam pib kis thoob plaws lub cell daim nyias nyias. Yog hais tias muaj yog stimulation ntawm M-choline receptor, cov hauj lwm tseem ceeb ua si los ntawm ob txib thiab cov G-nqaijrog nyob rau hauv lub teeb liab kis tau tus mob.

Acetylcholine ua nyob rau hauv ib tug heev luv luv lub sij hawm. Qhov no yog vim lub fact tias nws yog sai hydrolyzed los ntawm cov enzyme acetylcholinesterase. Choline, uas yog tsim nyob rau thaum lub sij hawm lub hydrolysis ntawm acetylcholine nyob rau hauv ib nrab volume ntawm presynaptic davhlau ya nyob twg yuav yog thiab thauj mus rau lub cytoplasm rau tom ntej biosynthesis ntawm acetylcholine.

Tshuaj uas ua rau lub cholinergic synapses

Pharmacological thiab ib tug ntau yam ntawm tshuaj muaj feem xyuam rau ib tug xov tooj ntawm dab uas yog txuam nrog rau synaptic kis tau tus mob:

• Txheej txheem acetylcholine synthesis.
• Txheej txheem daws kho tso tawm. Piv txwv li, carbacholine peev xwm ntawm mus pab tau txoj acetylcholine tso tawm cov txheej txheem, ib tug Kab mob Botulinum taug tej zaum yuav inhibit neurotransmitter tso tawm txheej txheem.
• Tus txheej txheem ntawm kev sis raug zoo ntawm acetylcholine thiab choline receptor.
• Hydrolysis ntawm acetylcholine enzymatic xwm.
• Tus capture ntawm choline, tsim los ntawm hydrolysis ntawm acetylcholine presynaptic davhlau ya nyob twg. Piv txwv li, yuav inhibit gemiholiny ntawm neuron capture thiab thauj ntawm choline mus rau hauv lub cell cytoplasm.

kev faib

Txhais tau hais tias stimulating lub cholinergic synapses, yuav muab tsis tau tsuas yog cov nyhuv, tiam sis cov anticholinergic (depressing) nyhuv. Raws li ib lub hauv paus rau lub kev faib xws li tshuaj biochemists siv cov kev taw qhia ntawm kev txiav txim ntawm cov tebchaw nyob rau txawv cholinergic receptors. Yog hais tias raws li ib tug hauv paus ntsiab lus, cov tshuaj uas cuam tshuam rau lub cholinergic receptors yuav dej num raws li nram no:

• Tshuaj uas muaj ib feem nyob rau M-cholinergic receptors thiab N-cholinergic receptors: ib tug holinomimetikami yog acetylcholine thiab carbacholine thiab holinoblokatoram - tsiklodol.
• anticholinesterase xwm txhais tau tias. Cov muaj xws li cov salicylate, physostigmine, Neostigmine, galantamine hydrobromide, Armin.
• Tshuaj uas cuam tshuam rau cholinergic synapses. Los ntawm cholinomimetics xws li pilocarpine hydrochloride thiab aceclidine rau holinoblokatoram - atropine sulfate, matatsin, tartrate platifillina, ipratropium bromide, hydrobromide skopalamina.

• Tshuaj nrog vlinyanie H-cholinergic receptors. Los ntawm holinomimetikami yog tsititon thiab lobeline hydrochloride. H blockers nicotinic acetylcholine receptor yuav tau muab faib ua ob pawg. Tus thawj - ib tug txhais tau tias ganglioblokiruyuschimi cim. Cov no muaj xws benzogeksony, gigrony, pentamin, arfonad, pyrylium. Qhov thib ob pab pawg neeg vkulyuchaet ib Curariform substance. Cov no muaj xws nqaij hnaiv, muab peripheral txiav txim xws li tubocurarine chloride, pancuronium bromide, bromide pipekuroniya.

Peb soj ntsuam nyob rau hauv kom meej qhov txhais tau tias ntawm rau cholinergic synapses.