Gamma-aminobutyric?acid,?or?GABA,?is?the?primary?INHIBITORY?neurotransmitter?in?the?mature?brain.

γ-氨基丁酸（GABA）是成熟大腦中主要的抑制性神經(jīng)遞質(zhì)。

It?REDUCES?neuronal?activity?of?target?cells?through?its?binding?to?GABA?receptors?present?on?the?cell?surface.

它通過與細(xì)胞表面的GABA受體結(jié)合，降低靶細(xì)胞的神經(jīng)元活性。

Nearly?half?of?all?synapses?of?the?brain?express?some?kind?of?GABA?receptor?and?are?thus?responsive?to?GABA.

幾乎一半的大腦突觸表達(dá)某種GABA受體，因此對(duì)GABA有反應(yīng)。

There?are?at?least?3?types?of?GABA?receptors:?GABA-A,?GABA-B?and?GABA-C.

GABA受體至少有3種類型：GABA-A、GABA-B和GABA-C。

GABA-A?and?GABA-C?are?ligand-gated?chloride?channels.

GABA-A和GABA-C是配體門控的氯離子通道。

Upon?transmitter?binding,?they?open?and?allow?chloride?ions?to?flow?into?the?neuron,?making?it?more?NEGATIVE,?or?HYPER-polarized,?and?thus?LESS?likely?to?generate?action?potentials.

當(dāng)遞質(zhì)結(jié)合時(shí)，它們打開，氯離子流入神經(jīng)元，神經(jīng)元呈負(fù)性或超極化，因此不太可能產(chǎn)生動(dòng)作電位。

GABA-B?acts?through?a G-protein?to?activate?potassium?channels,?which?allow?positively-charged?potassium?to?flow?OUT?of?the?cell,?again?resulting?in?membrane?HYPER-polarization?and?a?subsequent?decrease?in?neuron?responsiveness.

GABA-B通過G蛋白激活鉀通道，使帶正電荷的鉀從細(xì)胞中流出，再次導(dǎo)致細(xì)胞膜超極化，神經(jīng)元反應(yīng)性隨后降低。

GABA?is?believed?to?play?a?major?role?in?controlling?neuronal?hyperactivity?associated?with?fear,?anxiety?and?convulsions.

GABA在控制與恐懼、焦慮和驚厥相關(guān)的神經(jīng)元功能亢進(jìn)中起主要作用。

GABA-A?receptor?is?composed?of?5?protein?subunits.

GABA-A受體由5個(gè)蛋白亞基組成。

In?addition?to?binding?sites?for?GABA,?it?has?allosteric?binding?sites?for?other?substances?known?as?GABA?modulators.

除了GABA的結(jié)合位點(diǎn)外，它還具有其他物質(zhì)的變構(gòu)結(jié)合位點(diǎn)，即GABA調(diào)節(jié)劑。

These?are?molecules?that?can?INCREASE?or?DECREASE?the?action?of?GABA,?but?have?no?effect?in?the?absence?of?GABA.

這些分子可增強(qiáng)或降低GABA的作用，但在沒有GABA的情況下，不起作用。

For?example,?benzodiazepines, a?class?of?drugs?used?to?treat?anxiety,?bind?to?GABA-A?receptor?and?facilitate?its?binding?to?GABA,?thus?potentiating?GABA?inhibitory?effect.

例如，一類治療焦慮癥的藥物-苯二氮卓類與GABA-a受體結(jié)合，促進(jìn)其與GABA的結(jié)合，從而增強(qiáng)GABA的抑制作用。

Other?positive?modulators?include?barbiturates,?alcohol,?propofol,?among?others.

其他積極的調(diào)節(jié)劑包括巴比妥酸鹽、酒精、異丙酚等。

Examples?of?negative?modulators?are?convulsants,?such?as?Flumazenil.

負(fù)調(diào)節(jié)劑包括驚厥藥，如氟馬西尼。

Flumazenil?reverses?the?effects?of?benzodiazepines?by?competing?with?them?at?the?same?binding?site?on?GABA-A.

氟馬西尼競(jìng)爭(zhēng)苯二氮卓的GABA-A同一結(jié)合位點(diǎn)，逆轉(zhuǎn)其作用。

總結(jié):

1.GABA抑制性神經(jīng)遞質(zhì)。

2.GABA-A.GABA-C配體門控通道

GABA-A使氯離子內(nèi)流。

GABA-B鉀離子外流。

3.GABA調(diào)節(jié)劑:這些物質(zhì)可以增強(qiáng)或減少GABA的作用。