“…The exocrine functions of tachykinins by acting as antimicrobial peptides are also suspected in lower vertebrates, as tachykinin expression has been demonstrated in the skin of amphibians (Li et al, 2006) and more recently in fish species (Mi et al, 2010). To date, two groups of tachykinins, invertebrate tachykinins (Inv-TK) and tachykinin-related peptides (TKRP), have been reported in protostomic invertebrates, including insects (Predel et al, 2005;Siviter et al, 2000), mollusks (Kanda et al, 2003;Kanda et al, 2007), and echiuroid worms (Kawada et al, 1999), and more recently in coelenterates (Anctil, 2009) ( Table.1). In representative species of invertebrates, cognate receptors with differential selectivity for Inv-TK and TKRP respectively have been identified (Satake et al, 2013;Satake et al, 2003) and found to be functionally linked with Ca 2+ signaling (Torfs et al, 2002a;Torfs et al, 2002b), IP 3 production (Torfs et al, 2000) and cAMP production (Poels et al, 2005) similar to that of mammalian NKRs (see introduction for details).…”