gamma-aminobutyric acid (GABA, Gammalone, Mielomade)

Introduction

Major inhibitory neurotransmitter of the central nervous system. Highly concentrated in substantia nigra & globus pallidus. Also found in hypothalamus, periaquectal grey matter & hippocampus. GABA is removed from the synapse by active transport of astrocytes. GABA receptors are linked to chloride channels. Activation of benzodiazpine receptors enhances effects of GABA on GABA receptors.

In the fetus, GABA is an excitatory neurotransmitter. The surge of maternal oxytocin at birth affects chloride channels in fetal neurons, causing chloride concentrations to drop, and the switch from excitatory to inhibitory neurotransmitter.

Pathology

• 4-hydroxybutyricaciduria is an inborn error of GABA metabolism

Pharmacology

• gabapentin is structurally related to GABA, but does not interact with GABA receptors

Comparative biology

• in two rodent models of autism, chloride concentrations remain high & GABA remains an excitatory neurotransmitter after birth
• prenatal adminitration of bumetanide 1 day prior to delivery eliminated autistic behavior in the rodent offspring

More general terms

• carboxylate
• amine
• neurotransmitter

Additional terms

• gabapentin (Neurontin, Gralise)
• gamma amino butyric acid [GABA] receptor

Component of

• gamma aminobutyrate/melatonin/valeriana officinalis

Database

• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=119