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Actions of nematode FMRFamide-related peptides on the pharyngeal muscle of the parasitic nematode, Ascaris suum

Actions of nematode FMRFamide-related peptides on the pharyngeal muscle of the parasitic nematode, Ascaris suum
Actions of nematode FMRFamide-related peptides on the pharyngeal muscle of the parasitic nematode, Ascaris suum
The endogenous nematode peptides known as FMRFamide-related peptides (FaRPs) and various “classical” transmitters have a range of effects on nematodes that result in changes in behavior, particularly locomotion, including paralysis and inhibition of feeding. This study describes the application of an in vitro pharmacological approach to further delineate the action of a number of FaRP neurotransmitters on feeding behavior. Contraction of Ascaris suum pharyngeal muscle was monitored using a modified pressure transducer system that detects changes in intrapharyngeal pressure and therefore contraction of the radial muscle of the pharynx. The pharynx did not contract spontaneously. However, serotonin (5-HT, 100 µM) stimulated rhythmic contractions and relaxations (pumping) at a frequency of 0.5 Hz. The native nematode peptide, KNEFIRFamide (AF1), inhibited the pumping elicited by 5-HT. The duration of inhibition was concentration-dependent (1-1000 nM) with a threshold of 1 nM (n= 7). KSAYMRFamide (AF8/PF3) also inhibited pharyngeal pumping. There was no observable effect of any of the following nematode peptides on pharyngeal pumping behavior (1-1000 nM; n= 8): AF2, AF3, AF4, AF6, AF16, PF1/CF1, PF2/CF2, or PF4. Thus, interruption of pharyngeal processes, such as feeding, regulation of hydrostatic pressure, and secretion, may provide a new site of anthelmintic action.
0077-8923
228-238
Brownlee, D.J.A.
928c736f-1f5f-4c2a-8276-c8e7fea2e585
Walker, R.J.
b6597591-587e-488a-8a54-89156c42ce8d
Brownlee, D.J.A.
928c736f-1f5f-4c2a-8276-c8e7fea2e585
Walker, R.J.
b6597591-587e-488a-8a54-89156c42ce8d

Brownlee, D.J.A. and Walker, R.J. (1999) Actions of nematode FMRFamide-related peptides on the pharyngeal muscle of the parasitic nematode, Ascaris suum. Annals of the New York Academy of Sciences, 897 (1), 228-238. (doi:10.1111/j.1749-6632.1999.tb07894.x).

Record type: Article

Abstract

The endogenous nematode peptides known as FMRFamide-related peptides (FaRPs) and various “classical” transmitters have a range of effects on nematodes that result in changes in behavior, particularly locomotion, including paralysis and inhibition of feeding. This study describes the application of an in vitro pharmacological approach to further delineate the action of a number of FaRP neurotransmitters on feeding behavior. Contraction of Ascaris suum pharyngeal muscle was monitored using a modified pressure transducer system that detects changes in intrapharyngeal pressure and therefore contraction of the radial muscle of the pharynx. The pharynx did not contract spontaneously. However, serotonin (5-HT, 100 µM) stimulated rhythmic contractions and relaxations (pumping) at a frequency of 0.5 Hz. The native nematode peptide, KNEFIRFamide (AF1), inhibited the pumping elicited by 5-HT. The duration of inhibition was concentration-dependent (1-1000 nM) with a threshold of 1 nM (n= 7). KSAYMRFamide (AF8/PF3) also inhibited pharyngeal pumping. There was no observable effect of any of the following nematode peptides on pharyngeal pumping behavior (1-1000 nM; n= 8): AF2, AF3, AF4, AF6, AF16, PF1/CF1, PF2/CF2, or PF4. Thus, interruption of pharyngeal processes, such as feeding, regulation of hydrostatic pressure, and secretion, may provide a new site of anthelmintic action.

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Published date: December 1999
Organisations: Centre for Biological Sciences

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Local EPrints ID: 372597
URI: http://eprints.soton.ac.uk/id/eprint/372597
ISSN: 0077-8923
PURE UUID: 304e68ee-0cb3-4f74-9eff-75b56e19931d

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Date deposited: 09 Dec 2014 14:12
Last modified: 14 Mar 2024 18:39

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Contributors

Author: D.J.A. Brownlee
Author: R.J. Walker

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