Step-by-step explanation:
Γ-Aminobutyric acid (GABA) is a non-protein amino acid that is widely present in microorganisms, plants and animals. It is the main inhibitory neurotransmitter in the central nervous system (CNS) of mammals.
It plays the leading role in reducing neuronal excitability throughout the nervous system. In humans, GABA is directly responsible for the regulation of muscle tone.
Although, in chemical terms, it is an amino acid, in the scientific and medical communities they rarely refer to GABA as such because the term "amino acid" by convention refers to the α amino acids and GABA is not. It is also not considered as part of any protein.
In spastic diplegia in humans from an early age, GABA absorption is negatively affected by the nerves damaged by the lesion in the upper motor neurons characteristic of the condition which leads to the development of muscular hypertonia signaled by those nerves that are incapable of absorbing GABA.