Synthesis of γ‐Glutamyldopamine and Other Peptidoamines in the Nervous System of Aplysia californica

Abstract

The synthesis of a series of gamma-glutamyl amines (gamma-Glu-amines), including gamma-Glu-dopamine, gamma-Glu-5-hydroxytryptamine, gamma-Glu-octopamine, gamma-Glu-tryptamine, gamma-Glu-tyramine, and gamma-Glu-phenylethylamine, by nervous tissue of the marine mollusc Aplysia californica is described. After ganglia were incubated in vitro with 14C-amines, the unchanged amine and a new 14C-labeled product, identified as the gamma-Glu conjugate of the amine, were isolated from the tissue extracts. Identification was made by comparing the chromatographic properties (HPLC, TLC, and LC) of the isolated conjugates with chemically synthesized gamma-Glu-amines before and after acid hydrolysis.

Elicitation studies in cell suspension cultures of Cannabis sativa L.

“…Although, glutamyl-tyramine has been detected in the horseshoe crab Limulus polyphemus (Battelle et al, 1988) and in the snail Helix aspersa (Zhou et al, 1993), presence of glutamyl-tyramine has not been reported in plants so far. ␥-Glutamyl conjugates and tyramine conjugates have been identified as neurotransmitters in insects (Maxwell et al, 1980;Sloley et al, 1990), crustaceans (Battelle and Hart, 2002), mollusks (MacCaman et al, 1985;Karhunen et al, 1993) and mammals (Macfarlane et al, 1989). In plants such as soybean (Garcez et al, 2000), tomato (Zacares et al, 2007), rice (Jang et al, 2004), Lycium chinense (Han et al, 2002;Lee et al, 2004), Chenopodium album (Cutillo et al, 2003), Solanum melongena (Whitaker and Stommel, 2003), Citrus aurantium (Pellati and Benvenuti, 2007), Piper caninum (Ma et al, 2004) and Cyathobasis fructiculosa (Bunge) Aallen (Bahceevli et al, 2005), hydroxycinnamic acid conjugates such as the N-hydroxycinnamic acid amides and amine conjugates such as the phenethylamine alkaloids have been identified as constitutive, induced or overexpressed metabolites of plant defense.…”

Review of octopamine in insect nervous systems

“…103,104 Based on these findings, it is suggested that β-alanine, glutamate, and sulfate conjugation reactions may be other major pathways for inactivation of biogenic amines in the insect nervous system (Figure 3). Lastly, monoamine oxidase (the key enzyme in the monoamine inactivation pathway in vertebrates) plays a minor role in inactivating OCT in the insect nervous system.…”

Identification and Function of Octopamine and Tyramine Conjugates in the Limulus Visual System

“…y-GA synthetase activity was detected in nervous and nonnervous tissue of both Limulus and Aplysia (Table 1 and Stein and Weinreich, 1982). In Aplysia, the highest specific activity for the enzyme and the greatest accumulation of newly synthesized y-Glu amines were found in the capsule surrounding nervous tissue (Stein and Weinreich, 1983;McCaman et al, 1985). In Limulus, on the other hand, Glu TA.…”

“…These fibers are also the sites of OCT synthesis (Evans et al, 1983;Battelle and Evans, 1984). This is in contrast to the lobster (Homarus), where OCT metabolites accumulate in the glia surrounding the nervous system (Livingstone et al, 1980), and Aplysia where, as mentioned above, they are synthesized and accumulate preferentially in the capsule surrounding the nervous system (Stein and Weinreich, 1983;McCaman et al, 1985). Second, y-Glu OCT and y-Glu TA are released in a Ca2+-dependent manner when ventral and lateral eyes are depolarized with veratndine (but not with elevated K+) (Battelle and Evans, 1986 and this study, Fig.…”

“…The only other invertebrate reported to conjugate amines to glutamic acid is the sea snail Aplysia californica. y-Glutamylhistamine is a major product of histamine metabolism in Aplysia (Weinreich 1979;Stein and Weinreich, 1982), and the synthesis of a variety of y-Glu amines has been demonstrated in Aplysia pedal ganglia (McCaman et al, 1985). Interestingly, the formation of y-Glu amines has been demonstrated also in mammalian brain (Tsuji et al, 1977), although the enzyme responsible for their synthesis in mammalian brain (y-glutamyl transferase) differs from that in the invertebrate nervous system (Tsuji et al, 1977;Stein and Weinreich, 1982).…”