Distribution of Gaba and Other Amino Acids In Different Tissues of The Gastropod Mollusc Helix Pomatia, Including In Vitro Experiments With^,4c Glucose and^I4c Glutamic Acid

Abstract

Microchromatography on 3 x 3 cm polyamide layers of dansyl-compounds was used to study the distribution of free amino acids, GABA, serotonin, 5-hydroxyindole and 5-hydroxytryptophan in the brain, optic tentacle, pharyngeal retractor muscle and heart of Helix pomuriu. In addition the formation of GABA after incubation in U-I r C glucose or U-*rC glutamic acid was studied.Low amounts of GABA were for the first time shown to occur in all four tissues studied. In addition taurine, thought to be absent from terrestrial gastropods, was shown to occur in the snail's tissues.I n cirro incubation of brain and heart with 1% labelled glucose demonstrated the formation of 1% glutamic acid, 14C glutamine, 1 * c alanine and 1% aspartic acid. These amino acids, in addition to *4C GABA, were formed when brain and heart were incubated with 1-labelled glutamic acid. The distribution of amino acids in all other tissues studied showed some similarities, with the exception of ornithine which is low in the brain compared with the high amounts in tfre heart, pharynseal retractor mwcle and optic tentacle. The brain differs also from the other tissues studied in having a higher concentration of glycine, glutamic acid, serotonin and 5-hydroxytryptophan. Furthermore. 5-hydroxyindole was only found in the brain.

Localization of GABA-like immunoreactivity in the central nervous system ofAplysia californica

“…The presence of GABA in the molluscan central nervous system was first shown in the cephalopod, Eledone cirrhosa (Bradford et al, 1969;Cory and Rose, 1969), and subsequently demonstrated in the pulmonates Helix pomatia (Osborne et al, 1971;Dolezalova et al, 1973), Helix aspersa (Osborne, 1971), Achatina fulica (Takeuchi et al, 1977), and Helisoma trivolvis (Richmond et al, 1991). Of particular relevance to the present study are the findings of Cottrell (1974) who measured GABA levels in the various ganglia of Aplysia dactylomela.…”

“…Biochemical approaches demonstrated the presence of GABA, its synthesis, and its uptake in the central nervous systems of several molluscan species (Osborne et al, 1971;Dolezalova et al, 1973;Cottrell, 1974). The localization of GABA to specific neurons within molluscan nervous systems was shown by using autoradiographic and immunohistological techniques (Turner and Cottrell, 1978;Cooke and Gelperin, 1988;Richmond et al, 1991;Arshavsky et al, 1993;Hernadi, 1994;Norekian, 1999).…”

Development of the larval nervous system of the gastropod Ilyanassa obsoleta

“…While we likely uncovered a great proportion of the larval nervous system in I. obsoleta, still other neurons may exist. This seems especially likely since additional classical transmitters, such as acetylcholine (Twarog, 1954;Hanley and Cottrell, 1974;Chrachri and Williamson, 1998), GABA (Osborne et al, 1972;Walker et al, 1975;Morse et al, 1980;Cooke and Gelperin, 1988;Vitellaro-Zuccarello and De Biasi, 1988), and glutamate (Bolshakov et al, 1991;Dale and Kandel, 1993;Nesic et al, 1996;Michel et al, 2000) as well as various peptides (Croll and Van Minnen, 1992;Santama et al, 1994;Willows et al, 1997) are utilized in adult molluscan neurons. Furthermore, we have recently localized histamine in larval stages of I. obsoleta (unpubl.…”

Tryptophan metabolism in characterized neurones of Helix

“…A microbiochemical method (Neuhoff, 1971;Osborne, Briel & Neuhoff, 1971) was used in this study to observe the metabolism of [14C]-tryptophan in two specific types of giant cells in the snail Helix pomatia. One type of cell (GSC) situated in each cerebral ganglion is known to contain 5-hydroxytryptamine (Cottrell & Osborne, 1970), while the other, situated in each buccal ganglion, lacks this amine (Osborne & Cottrell, 1972a (Osborne, 1972a) and that both cell types contain tryptophan (Briel, Neuhoff & Osborne, 1972;Osborne & Cottrell, 1972a).…”