Occurrence and neuroendocrine role of D-aspartic acid and N-methyl-D-aspartic acid in Ciona intestinalis.
Probes for the occurrence of endogenous D-aspartic acid (D-Asp) and N-methyl-D-aspartic acid (NMDA) in the neural complex and gonads of a protochordate, the ascidian Ciona intestinalis, have confirmed the presence of these two excitatory amino acids and their involvement in hormonal activity. A hormonal pathway similar to that which occurs in vertebrates has been discovered. In the cerebral ganglion D-Asp is synthesized from L-Asp by an aspartate racemase. Then, D-Asp is transferred through the blood stream into the neural gland where it gives rise to NMDA by means of an NMDA synthase. NMDA, in turn, passes from the neuronal gland into the gonads where it induces the synthesis and release of a gonadotropin-releasing hormone (GnRH). The GnRH in turn modulates the release and synthesis of testosterone and progesterone in the gonads, which are implicated in reproduction.
D'Aniello
Antimo
A
Laboratory of Neurobiology, Stazione Zoologica 'A. Dohrn', Villa Comunale, 80121 Naples, Italy. daniello@szn.it
Spinelli
Patrizia
P
De Simone
Antonietta
A
D'Aniello
Salvatore
S
Branno
Margherita
M
Aniello
Francesco
F
Fisher
George H
GH
Di Fiore
Maria M
MM
Rastogi
Rakesh K
RK
D000818:Animals; D001224:Aspartic Acid / Q000737:chemistry / Q000502:physiology*; D002938:Ciona intestinalis / Q000378:metabolism* / Q000502:physiology; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000502:physiology; D006066:Gonads / Q000378:metabolism; D066298:In Vitro Techniques; D007447:Invertebrate Hormones / Q000737:chemistry / Q000502:physiology; D008297:Male; D016202:N-Methylaspartate / Q000737:chemistry / Q000502:physiology*; D009490:Neurosecretory Systems / Q000502:physiology; D011374:Progesterone / Q000096:biosynthesis; D012098:Reproduction; D013237:Stereoisomerism; D013739:Testosterone / Q000096:biosynthesis
D007447:Invertebrate Hormones; D001224:Aspartic Acid; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D011374:Progesterone; D016202:N-Methylaspartate