Central nervous system. This amino acid is widely distributed not only in our
physiological system but is also present in plants, animals, and micro-organisms
where its role in Krebs cycle is known in plants and microbes while in animals as a
neural signal neurotransmitter. Its wide applications in pharmaceutical, medical,
nutraceuticals and recently for manufacturing of nylon and other compounds make
this simple amino acid “GABA” very important (Dhakal et al. 2012; Dai-Hung and
Sang 2019).
GABA binds to GABA receptors which are sub-classified as GABA-A and
GABA-B. Another minor class GABA-C has also been reported and it has a major
role in retinal signal processing. GABA is biosynthesized from L-glutamic acid by
the decarboxylation reaction catalyzed by Glutamate decarboxylase (GAD, EC
4.1.1.15) and pyridoxal phosphate (PLP) that acts as a cofactor. GABA after
biosynthesis gets packaged into synaptic vesicles by VGAT (vesicular GABA
transporter) (Fig. 24.1), later released in the synaptic cleft and then binds to the
GABA receptors on postsynaptic region which is either GABA-A or GABA-B.
Though the main concern of this chapter is not to deal with GABA receptors, we are
presenting in very brief these receptors for reader's concerns. Both receptors vary in
their physiological and pharmacological properties. GABA-A receptors are ligand
gated chloride channel receptors located post-synaptically while GABA-B is
GPCR’s located pre as well as post-synaptic. On one hand, GABA-A receptors are
involved in mediating cardiovascular, anti-anxiety and anti-convulsive activities
while on the other hand, GABA–B receptors are mainly indulged in depression and
analgesic effects (Matsumoto 1989; Diana et al. 2014; Richard and Timothy 1999).
Fig. 24.1 Biosynthesis of GABA and its fate in Glia
820
P. Jain and M. S. Ghodke
physiological system but is also present in plants, animals, and micro-organisms
where its role in Krebs cycle is known in plants and microbes while in animals as a
neural signal neurotransmitter. Its wide applications in pharmaceutical, medical,
nutraceuticals and recently for manufacturing of nylon and other compounds make
this simple amino acid “GABA” very important (Dhakal et al. 2012; Dai-Hung and
Sang 2019).
GABA binds to GABA receptors which are sub-classified as GABA-A and
GABA-B. Another minor class GABA-C has also been reported and it has a major
role in retinal signal processing. GABA is biosynthesized from L-glutamic acid by
the decarboxylation reaction catalyzed by Glutamate decarboxylase (GAD, EC
4.1.1.15) and pyridoxal phosphate (PLP) that acts as a cofactor. GABA after
biosynthesis gets packaged into synaptic vesicles by VGAT (vesicular GABA
transporter) (Fig. 24.1), later released in the synaptic cleft and then binds to the
GABA receptors on postsynaptic region which is either GABA-A or GABA-B.
Though the main concern of this chapter is not to deal with GABA receptors, we are
presenting in very brief these receptors for reader's concerns. Both receptors vary in
their physiological and pharmacological properties. GABA-A receptors are ligand
gated chloride channel receptors located post-synaptically while GABA-B is
GPCR’s located pre as well as post-synaptic. On one hand, GABA-A receptors are
involved in mediating cardiovascular, anti-anxiety and anti-convulsive activities
while on the other hand, GABA–B receptors are mainly indulged in depression and
analgesic effects (Matsumoto 1989; Diana et al. 2014; Richard and Timothy 1999).
Fig. 24.1 Biosynthesis of GABA and its fate in Glia
820
P. Jain and M. S. Ghodke