Comparative studies on glutamate decarboxylase and choline acetyltransferase activities in the vertebrate vestibule.
1. Vestibular putative neurotransmitters GABA and acetylcholine synthesizing enzymes were quantified in four vertebrate species to find a correlation between all-vertebrate vestibular hair cell II (HCII) and synaptic contacts and appearance of hair cell I (HCI) and related synapses in terrestrial species. 2. Glutamate decarboxylase (GAD) and choline acetyltransferase (ChAT) values were: 3.76; 15.38; 21.68; 27.78 and 9.44; 450; 720; 970 n(pico)mol/mg protein/hr (min) in, respectively, frogs, guinea pigs, rats and chicks. 3. GAD and ChAT omnipresence may indicate constant GABAergic HCII and its cholinergic efferent synapses, their raised content, appearance of GABA-containing HCI and related cholinergic boutons in higher vertebrates.
López
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I
Departamento de Neurociencias, Instituto de Fisiología Celular, México.
Meza
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G
D000818:Animals; D002645:Chickens; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D005968:Glutamate Decarboxylase / Q000378:metabolism*; D006168:Guinea Pigs; D011898:Ranidae; D051381:Rats; D014714:Vertebrates / Q000378:metabolism*; D014722:Vestibule, Labyrinth / Q000201:enzymology*
D002795:Choline O-Acetyltransferase; D005968:Glutamate Decarboxylase