An Attempt to Identify Putative Neurotransmitter Molecules in the Central Nervous System of the Snail

Abstract

Two classes of substances, amines and amino acids, were investigated as potential neurotransmitters in the central nervous system of the snail HeIix pomatiu. The authors were able to demonstrate the presence of physiologically important amines and amino acids such as 5-HT, tyramine, tryptamine, adrenaline, noradrenaline, dopamine, and Dopa in all parts of the brain. GABA was found to be present mostly in its y-lactame form and its identity was verified by using mass spectrometry. The presence of polyamines such as putrescine, spermine and spermidine was also established by means of mass spectrometry.Several indol-derivates such as tryptophan, 5-HTP, 6-HTP and 5-HT, 6-HT and 5,6-HT were found to be present.Amines and amino acids differed both qualitatively and quantitatively among the different parts of the snail brain, however, no differences in composition were discovered between left and right ganglia. 7 Present address : Laboratory of Neuropsychopharmacology, Int J Neurosci Downloaded from informahealthcare.com by Mcgill University on 12/14/14 For personal use only. T LC MS FIGURE 2 amino acids. Schematic diagram of the procedure used for the separation and the identification of amines and Int J Neurosci Downloaded from informahealthcare.com by Mcgill University on 12/14/14For personal use only.

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).…”

GABA‐like immunoreactivity in Biomphalaria: Colocalization with tyrosine hydroxylase‐like immunoreactivity in the feeding motor systems of panpulmonate snails

“…In gastropod molluscs, a neurotransmitter role for GABA was initially suggested by pharmacological studies in which it was found to produce both excitatory and inhibitory responses upon application to snail neurons (Gerschenfeld & Tauc, ; Walker, Crossman, Woodruff, & Kerkut, ; Walker, Aranza, Kerkut, & Woodruff, ). Biochemical approaches demonstrated the presence of GABA, its synthesis, and its uptake in the central nervous systems of several gastropod species (Cottrell, ; Dolezalova, Giacobini, & Stepita‐Klauco, ; Osborne, Briel, & Neuhoff, ). The localization of GABA to specific neurons within gastropod nervous systems was demonstrated with autoradiographic and immunohistological techniques in Planorbis (Turner & Cottrell, ), Limax (Cooke & Gelperin, ), Helisoma (Richmond, Bulloch, Bauce, & Lukowiak, ), Clione (Arshavsky et al, ; Norekian, ), Helix (Hernádi, ), Aplysia (Díaz‐Ríos et al, ), Pleurobranchaea , and four nudibranchs species (Gunaratne, Sakurai, & Katz, ; Gunaratne & Katz, ).…”