title: GABA may be a neurotransmitter in the vertebrate peripheral nervous system.
abstract: gamma-Aminobutyric acid (GABA) is an inhibitory neurotransmitter in the peripheral nervous system of certain invertebrates and is thought to be a major transmitter in the vertebrate central nervous system. In this report we present evidence that GABA may also be a neurotransmitter in the vertebrate peripheral autonomic nervous system. We have used light and electron microscopic autoradiography to analyse high-affinity uptake of 3H-GABA into the myenteric plexus of the guinea pig taenia coli, both in situ and in a tissue culture preparation. In the isolated myenteric plexus, we have measured the specific activity of glutamic acid decarboxylase (GAD; EC 4.1.1.15), the enzyme responsible for conversion of glutamic acid to GABA in GABAergic neurones, and assessed the ability of this tissue to accumulate 3H-GABA newly synthesised from 3H-glutamic acid. Furthermore, we have measured the levels of endogenous GABA in strips of taenia coli containing the myenteric plexus.
mesh_terms: D000818:Animals; D001345:Autoradiography; D001692:Biological Transport; D002262:Carboxy-Lyases / Q000378:metabolism*; D005968:Glutamate Decarboxylase / Q000378:metabolism*; D005971:Glutamates / Q000378:metabolism; D006168:Guinea Pigs; D008854:Microscopy, Electron; D009197:Myenteric Plexus / Q000502:physiology*; D009474:Neurons / Q000378:metabolism; D010525:Peripheral Nerves / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
chemical_list: D005971:Glutamates; D005680:gamma-Aminobutyric Acid; D002262:Carboxy-Lyases; D005968:Glutamate Decarboxylase