Gamma amino butyrate is synthesized from
**Core Concept**
Gamma amino butyrate (GABA) is an inhibitory neurotransmitter in the central nervous system. It plays a crucial role in regulating neuronal excitability, muscle tone, and synaptic plasticity. The synthesis of GABA involves a two-step process involving the enzyme glutamic acid decarboxylase (GAD).
**Why the Correct Answer is Right**
GABA is synthesized from glutamate, which is the primary excitatory neurotransmitter in the central nervous system. The enzyme glutamic acid decarboxylase (GAD) catalyzes the decarboxylation of glutamate to form GABA. This reaction is essential for maintaining the balance between excitation and inhibition in the brain. The correct answer is **glutamate**, as it is the direct precursor to GABA.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because GABA is not synthesized from glucose directly. While glucose is an essential energy source for neurons, it is not a direct precursor to GABA.
**Option B:** This option is incorrect because GABA is not synthesized from aspartate. Aspartate is another excitatory neurotransmitter, but it is not involved in the synthesis of GABA.
**Option C:** This option is incorrect because GABA is not synthesized from glycine. Glycine is an inhibitory neurotransmitter, but it is not a precursor to GABA.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that GABA receptors are targeted by several classes of medications, including benzodiazepines, barbiturates, and anticonvulsants. These medications can either enhance or inhibit GABAergic activity, leading to various therapeutic effects.
**Correct Answer:** D. glutamate