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Nematode neuropeptide modulation of the vagina vera of Ascaris suum: in vitro effects of PF1, PF2, PF4, AF3 and AF4

Published online by Cambridge University Press:  01 January 2000

R. A. FELLOWES ,
A. G. MAULE ,
N. J. MARKS ,
T. G. GEARY ,
D. P. THOMPSON  and
D. W. HALTON
R. A. FELLOWES
Affiliation:
Parasitology Research Group, The School of Biology and Biochemistry, The Queen's University of Belfast, Belfast BT9 7BL, UK
A. G. MAULE
Affiliation:
Parasitology Research Group, The School of Biology and Biochemistry, The Queen's University of Belfast, Belfast BT9 7BL, UK
N. J. MARKS
Affiliation:
Parasitology Research Group, The School of Biology and Biochemistry, The Queen's University of Belfast, Belfast BT9 7BL, UK
T. G. GEARY
Affiliation:
Pharmacia and Upjohn Company, Kalamazoo, MI 49001, USA
D. P. THOMPSON
Affiliation:
Pharmacia and Upjohn Company, Kalamazoo, MI 49001, USA
D. W. HALTON
Affiliation:
Parasitology Research Group, The School of Biology and Biochemistry, The Queen's University of Belfast, Belfast BT9 7BL, UK
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Abstract

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Ascaris suum possesses a large number of FMRFamide-related peptides (FaRPs) of which KNEFIRFamide (AF1), KHEYLRFamide (AF2) and KSAYMRFamide (AF8/PF3) have been shown to modulate the intrinsic, rhythmic activity of the vagina vera of A. suum in vitro. In the present study, the effects of the nematode FaRPs, SDPNFLRFamide (PF1), SADPNFLREamide (PF2) and KPNFIRFamide (PF4) (from Panagrellus redivivus) and AVPGVLRFamide (AF3) and GDVPGVLRFamide (AF4) (from A. suum) on the in vitro activity of the vagina vera were examined. The effects of each of the peptides were qualitatively and quantitatively distinct. All 3 FaRPs from P. redivivus were inhibitory, causing a cessation of contractions. PF2 was 3 times more potent than PF1, with a threshold of 1 nM. Although PF4 was the least potent (threshold, 10 nM), its effects at [ges ]10 nM were quantitatively the greatest. Both AF3 and AF4 (1 μM) induced complex, multiphasic responses consisting of an initial contraction and spastic paralysis followed by a return of contractile activity of increased amplitude. AF3 was 3 times more potent than AF4. The effects of these peptides had some similarities to those observed on A. suum somatic body wall muscle in vitro, with PF1, PF2 and PF4 being inhibitory and AF3 and AF4 being excitatory.

Keywords

Ascaris suumnematodereproductive systemvaginagonoductneuropeptidesFaRPRFamidemuscle activity
Type
Research Article
Information
Parasitology , Volume 120 , Issue 1 , January 2000 , pp. 79 - 89
Copyright
2000 Cambridge University Press