Three more novel FMRFamide-like neuropeptide sequences from the eyestalk of the giant freshwater prawn Macrobrachium rosenbergii☆

The Neuromuscular Junctions of the Slow and the Fast Excitatory Axon in the Closer of the CrabEriphia spinifronsAre Endowed with Different Ca2+Channel Types and Allow Neuron-Specific Modulation of Transmitter Release by Two Neuropeptides

“…The effect of Ni 2ϩ was largely reversible after 20 min of washing with saline. 15.0 Ϯ 6.4 (n ϭ 8) (n ϭ 7) (n ϭ 6) (n ϭ 8) (n ϭ 11) (n ϭ 5) I (nA) (%) 73.5 Ϯ 4.9 2.3 Ϯ 1.5 35.0 Ϯ 3.9 77.8 Ϯ 6.1 20.6 Ϯ 4.4 13.0 Ϯ 3.8 (n ϭ 10) (n ϭ 7) (n ϭ 6) (n ϭ 11) (n ϭ 10) (n ϭ 6) The modulation of transmitter release by the peptide DF 2 involves -conotoxin-sensitive Ca 2؉ channels As many as 12 LRFamide-like peptides have been identified in crustaceans (Weimann et al, 1993;Sithigorngul et al, 1998Sithigorngul et al, , 2001Mercier et al, 2001), of which four have been shown to modulate transmitter release from neuromuscular endings in crayfish and lobster (Kravitz et al, 1980;Mercier et al, 1990;Skerrett et al, 1995;Worden et al, 1995;Jorge-Rivera and Marder, 1996;Friedrich et al, 1998). Among them is DRNFLRFamide, also referred to as DF 2 , which enhances junction potential amplitudes by increasing the number of transmitter quanta released (Skerrett et al, 1995).…”

Crustacean neuropeptides

“…While a number of techniques, including ones similar to those used for the isolation and characterization of RPCH, continue to be employed for peptide discovery [18][19][20], the emphasis has shifted from the purification and structural elucidation of targeted neuropeptides to an emphasis on peptidomics, the qualitative and quantitative characterization of the complement of endogenous bioactive peptides present in a species. When genomic/transcriptomic information is available, it is possible to use bioinformatics techniques to identify neuropeptide genes and apply processing models to predict neuropeptide sequences.…”

“…Many of these peptides possess the C-terminal motif -FLRFamide [13,19,23,25,48,51,52,72,79,155,157,[159][160][161]. In fact, the first FLPs identified from crustaceans contain this structural element, i.e., TNRNFLRFamide and SDRNFLRFamide from Homarus americanus [13].…”

Physiological functions of FMRFamide‐like peptides (FLPs) in crustaceans

“…The stomatogastric nervous system of Cancer borealis (Weimann et al, 1993) contains at least one of the peptides (TNRNFLRFamide) and also appears to contain another (SDRNFLRFamide). Eight FLPs were iso-lated from the eyestalk of the giant freshwater prawn, Macrobrachium rosenbergii (Sithigorngul et al, 1998(Sithigorngul et al, , 2001) including one that is identical to one of the crayfish peptides (DRNFLRFamide). A comparison of the peptide sequences reveals some common features.…”