trans

NEUROTRANSMITTERS IN NEMATODES 379
invertebrates. The widespread occurrence of
FaRPs in nematodes underlines their important
role in nematode biology (Table 15.4). Fewer
FaRPs have been isolated from vertebrates,
and they possess a structure different from the
nematode FaRPs, suggesting that nematode
FaRP receptors may be potential anthelmintic
targets.
All of the FaRPs identified in nematodes act
on the neuromuscular system. The majority
TABLE 15.4
Some FMRFamides from nematodes
FaRP 1 Amino acid sequence 2 Occurrence 3
AF1 KNEFIRF.NH 2 A
AF2 KHEYLRF.NH 2 A, C, H, P
AF3 AVPGVLRF.NH 2 A
AF4 GDVPGVLRF.NH 2 A
AF5 SGKPTFIRF.NH 2 A
AF6 FIRF.NH 2 A
AF7 AGPRFIRF.NH 2 A
AF8/PF3 KSAYMRF.NH 2 A, P
AF9 GLGPRPLRF.NH 2 A
AF10 GFGDEMSMPGVLRF.NH 2 A
AF11 SDIGISEPNFLRF.NH 2 A
AF12 FGDEMSMPGVLRF.NH 2 A
CF1/PF1 SDPNFLRF.NH 2 C, P
CF2/PF2 SADPNFLRF.NH 2 C, P
CF3 SQPNFLRF.NH 2 C
CF4 ASGDPNFLRF.NH 2 C
CF5 AAADPNFLRF.NH 2 C
CF6 PNFLRF.NH 2 C
CF7 AGSDPNFLRF.NH 2 C
(K)PNFMRY.NH 2
APEASPFIRF.NH 2
C
KPSFVRF.NH 2
C
PF4 KPNFIRF.NH 2 C, P
AF13 SDMPGVLRF.NH 2 A
AF14 SMPGVLRF.NH 2 A
AF15 AQTFVRF.NH 2 A
AF16 ILMRF.NH 2 A
AF17 FDRDFMHF.NH 2 A
AF19 AEGLSSPLIRF.NH 2 A
AF20 GMPGVLRF.NH 2 A
1 The compounds were originally named with a letter to denote the species
from which the peptide was isolated, F for FaRP, and a sequential number; thus
AF1 was the first FaRP found in A. suum. As more peptides were discovered,
often due to the use of different solvents for extraction, some were found to
exist in more than one nematode species. For example, AF8 is the same as PF3;
PF1 is the same as CF1; PF2 is the same as CF2.
2 The amino acid sequence is shown in single letter notation.
3 A, Ascaris suum; C, Caenorhabditis elegans; H, Haemonchus contortus;
P, Panagrellus redivivus.
BIOCHEMISTRY AND CELL BIOLOGY: HELMINTHS