Structural Characterization of a Diuretic Peptide from the Central Nervous System of the Leech Erpobdella octoculata

Salzet, Michel; Bulet, Philippe; Wattez, Christian; Verger-Bocquet, Martine; Malecha, Jean

doi:10.1074/jbc.270.4.1575

Cited by 42 publications

(26 citation statements)

References 22 publications

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“…Moreover, we have established that the AI! amount greatly increased just after a blood meal [1] and we speculate that AII, AIII and IV increase diuresis by acting on their different targets as tegument, stomach or nephridia [1,3]. These data allow us to present the kinetic scheme of the relations existing between a blood meal, effective diuresis and the central nervous system (CNS) in which the angiotensin metabolism takes place.…”

Section: Resultsmentioning

confidence: 99%

“…According to Wenning [21], stimulation of abdominal stretch receptors during feeding would cause hormonal release from the CNS. One of the hormone systems implicated in such a phenomenon is the angiotensins in leeches [1][2][3]. If we try to connect this physiological event to the enzymes involved in metabolism of angiotensins in CNS, we can distinguish three implicated enzymes: the ACE-like, the NEPlike enzymes and the AP whose efficiencies are in line with those of vertebrates [19].…”

Section: Resultsmentioning

confidence: 99%

“…This material was isolated from T. tessulatum and corresponded to the vertebrate AII and AIII, as well as fragments (3)(4)(5)(6)(7)(8) and (6--8) of All [2], suggesting the existence of peptidases involved in the metabolism of AII. Moreover, in Erpobdella octoculata, an angiotensin II-amide, differing from the vertebrate AII by a carboxyterminal amidation, has been sequenced [3]. Although the All-like peptide is very similar to the vertebrate All, its precursor seems to be different from the vertebrates one, the angiotensinogen protein of ca.…”

Section: Introductionmentioning

confidence: 95%

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Metabolism of angiotensins by head membranes of the leech Theromyzon tessulatum

Laurent

1996

FEBS Letters

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Angiotensins (angiotensin I, angiotensin II, angiotensin II-amide) have been isolated in leeches and such peptides are involved in diuresis in these animals. To explore possible inactivation mechanisms of these peptides, angiotensins were incubated with head membranes of the leech T. tessulatum. Membranes derived from head parts of this leech are very rich in peptidases. They contain endopeptidase-24.11-1ike enzyme (NEP-like) associated with a battery of exopeptidase. The way that angiotensins are degraded by the combined attack of these membrane peptidases has been investigated. The contribution of individual peptidases was assessed by adding inhibitors (phosphoramidon, captopril and amastatin) to the membrane fractions, when they were incubated with the peptides. In the case of angiotensin I, the primary attack was performed by a combined action of the NEP-like and the ACE-like enzymes, followed by aminopeptidase attacks. Angiotensin II and III were hydrolyzed by NEP-like enzyme at the same Tyr-Ile bond, whereas the Nterminal arginine residue of angiotensin IH was removed by an arginyl aminopeptidase. These results show that angiotensins are efficiently degraded by membranes and that NEP-like enzyme plays a key role in this process.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

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Metabolism of angiotensins by head membranes of the leech Theromyzon tessulatum

Laurent

1996

FEBS Letters

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“…However, research on this subject has been confined to this phylum, despite the fact that components of RAS have been described in invertebrates: for example, angiotensin II and I in leeches (51,52), angiotensinogenlike epitopes in the nervous system of Aplysia (53) and angiotensin-converting enzyme-like activity in blue crabs (54), reflecting the high conservation of angiotensins in the course of evolution. Therefore, it seemed justified to explore the influence of angiotensins on Chasmagnathus LTH (32,35).…”

Section: Components Of the Renin-angiotensin System (Ras) Are Involvementioning

confidence: 99%

Long-term habituation (LTH) in the crab Chasmagnathus: a model for behavioral and mechanistic studies of memory

Maldonado¹,

Romano²,

Tomsic³

1997

Braz J Med Biol Res

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A decade of studies on long-term habituation (LTH) in the crab Chasmagnathus is reviewed. Upon sudden presentation of a passing object overhead, the crab reacts with an escape response that habituates promptly and for at least five days. LTH proved to be an instance of associative memory and showed context, stimulus frequency and circadian phase specificity. A strong training protocol (STP) (≥15 trials, intertrial interval (ITI) of 171 s) invariably yielded LTH, while a weak training protocol (WTP) (≤10 trials, ITI = 171 s) invariably failed. STP was used with a presumably amnestic agent and WTP with a presumably hypermnestic agent. Remarkably, systemic administration of low doses was effective, which is likely to be due to the lack of an endothelial blood-brain barrier. LTH was blocked by inhibitors of protein and RNA synthesis, enhanced by protein kinase A (PKA) activators and reduced by PKA inhibitors, facilitated by angiotensin II and IV and disrupted by saralasin. The presence of angiotensins and related compounds in the crab brain was demonstrated. Diverse results suggest that LTH includes two components: an initial memory produced by spaced training and mainly expressed at an initial phase of testing, and a retraining memory produced by massed training and expressed at a later phase of testing (retraining). The initial memory would be associative, context specific and sensitive to cycloheximide, while the retraining memory would be nonassociative, context independent and insensitive to cycloheximide. Key wordsSimple and basic models to study memory Simple-system approaches using invertebrate species have led to considerable progress in our understanding of the mechanisms underlying learning and memory (e.g., the mollusks Aplysia (1,2) and Hermissenda (3,4), the fruit fly Drosophila (5), and the honey bee Apis (6)). A virtue usually attributed to invertebrates is that they are simple models though the use of this term has been highly controversial. Indeed, the CNS of invertebrates cannot be considered simple from the perspective of a neural network researcher since the amount of neurons involved in a current mnemonic process is assumed to be far larger than that required to obtain a satis-

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“…Phe, Leu, Trp, Tyr) and in particular phenylalanine [I 21. Neuropeptides isolated to date from leeches that could be NEP substrates include the following: angiotensin I [24], angiotensin 11-amide [25], RF-amides [26], enkephalins [ 131, y-MSH-like peptide [27], and lysine-conopressin [18]. Whether the phosphoramidon-sensitive endopeptidase is involved in the metabolism of these various leech neuropeptides remains to be established.…”

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confidence: 99%

Isolation of a Neuropeptide‐Degrading Endopeptidase from the Leech Theromyzon tessulatum

Laurent¹

1995

European Journal of Biochemistry

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Extracts of head parts prepared from the leech Theronzyznrz tessulutum hydrolyse the Gly3-Phe4 bond of synthetic [D-Ala2, LeuSIenkephalin and the Gly-His bond of benzoyl-Gly-His-Leu. The metabolism of benzoyl-Gly-His-Leu was completely inhibited by captopril, consistent with an angiotensin-converting enzyme activity. Such an enzyme has recently been isolated from 7: tessulatum. However, the enkephalin hydrolysis by captopril (100 pM) was inhibited to a maximum of 70 %. The residual activity hydrolyzing enkephalin was inhibited by phosphoramidon, consistent with the presence of endopeptidase-24.11, a mammalian enzyme implicated in the metabolism of neuropeptides. This enzyme was isolated using four steps of purification including gel-permeation and anion-exchange chromatographies followed by reversephase HPLC. This neuropeptide endopeptidase (of approximate molecular mass 45 kDa) hydrolyses, at pH 7 and 37"C, both the Cly3-Phe4 bond of synthetic [~-A l a 2 , LeuSjenkephalin and the Phe8-His9 bond of angiotensin 1. Cleavage of [D-Ala2, LeuSIenkephalin yields, respectively, the Tyr-D-Ala-Gly and PheLeu peptides with a specific activity of 29 nmol Tyr-D-Ala-Gly . min-I . mg protein-' (K,,, 95 pM). The hydrolysis of angiotensin I yields angiotensin I1 and the dipeptide His-Leu with a specific activity of 1.2 nmol angiotensin min-' . mg protein ~ I (K,,? 330 pM). The metabolism of these peptides was totally inhibited by phosphoramidon. This study therefore provides biochemical evidence for neuropeptide-degrading endopeptidases in leeches.Keywords: angiotensin-converting enzyme ; leech; neuropeptides; neutral endopeptidase; peptidase. In comparison with the mammalian system, relatively little is known about the inactivation of neuropeptides in invertebrates, but it is likely that similar enzyme mechanisms operate at the synaptic level. Neuropeptide-degrading endopeptidases were found in hemolymph of the mollusk Mytilus edulis 191, the crayfish A.ytacu.r polyphemus, and the horse shoe crab Limulus polyphemus [lo]. Moreover, an ACE-like enzyme, similar to vertebrate ACE, has been isolated from the insect Muscu domestica [I I ] and an endopeptidase-24.1 I-like enzyme has been isolated Correspondence to

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Structural Characterization of a Diuretic Peptide from the Central Nervous System of the Leech Erpobdella octoculata

Cited by 42 publications

References 22 publications

Metabolism of angiotensins by head membranes of the leech Theromyzon tessulatum

Metabolism of angiotensins by head membranes of the leech Theromyzon tessulatum

Long-term habituation (LTH) in the crab Chasmagnathus: a model for behavioral and mechanistic studies of memory

Isolation of a Neuropeptide‐Degrading Endopeptidase from the Leech Theromyzon tessulatum

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