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The effects of the nematode peptide, KHEYLRFamide (AF2), on the somatic musculature of the parasitic nematode Ascaris suum

Published online by Cambridge University Press:  06 April 2009

F. Y. Pang ,
J. Mason ,
L. Holden-Dye ,
C. J. Franks ,
R. G. Williams  and
R. J. Walker
F. Y. Pang
Affiliation:
Department of Physiology and Pharmacology, University of Southampton, Bassett Crescent East, Southampton SO16 7PX
J. Mason
Affiliation:
Department of Physiology and Pharmacology, University of Southampton, Bassett Crescent East, Southampton SO16 7PX
L. Holden-Dye
Affiliation:
Department of Physiology and Pharmacology, University of Southampton, Bassett Crescent East, Southampton SO16 7PX
C. J. Franks
Affiliation:
Department of Physiology and Pharmacology, University of Southampton, Bassett Crescent East, Southampton SO16 7PX
R. G. Williams
Affiliation:
Department of Physiology and Pharmacology, University of Southampton, Bassett Crescent East, Southampton SO16 7PX
R. J. Walker
Affiliation:
Department of Physiology and Pharmacology, University of Southampton, Bassett Crescent East, Southampton SO16 7PX
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Summary

AF2 is an endogenous RFamide-like peptide from the parasitic nematode Ascaris suum. The potent stimulatory effects of this peptide on the somatic musculature of Ascaris strongly suggest that it may have an important role in the motornervous system. Here we have investigated the possibility that AF2 may elicit a stimulatory action on Ascaris muscle by potentiating the actions of the excitatory cholinergic motornervous system either pre-synaptically, post-synaptically or both. In in vitro pharmacological experiments AF2 produced a dose-dependent increase in the frequency and amplitude of spontaneous contractions of Ascaris muscle strip which lasted for more than 1 h after a 3 min application of AF2 (10 nM–10µM; N = 7). In addition, AF2 (100 nM) potentiated the contraction elicited by ACh by 43 ± 9% (P < 0·01; N = 8). In electro-physiological recordings from muscle cells, AF2 (10–100 nM; N = 10) potentiated the amplitude of EJPs (excitatory junction potentials). For 100 nM AF2, the potentiation of the EJP was 218 ± 48% (N = 7; P < 0·01). This effect reversed after a wash of 10 min. AF2 did not potentiate the depolarization of the muscle cell elicited by bath applied ACh. These latter two observations are consistent with a presynaptic action of AF2. AF2 (10–100 nM) generated spontaneous muscle cell action potentials in previously quiescent cells. This effect took more than 1 h to wash out. These observations are discussed in terms of the paralysis of Ascaris that is elicited by AF2.

Keywords

neuropeptideAF2Ascaris.
Type
Research Article
Information
Parasitology , Volume 110 , Issue 3 , April 1995 , pp. 353 - 362
Copyright
Copyright © Cambridge University Press 1995

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References

REFERENCES

Baldwin, E. & Moyle, V. (1949). A contribution to the physiology and pharmacology of Ascaris lumbricoides. British Journal of Pharmacology 4, 145–52.Google Scholar
Colquhoun, L., Holden-Dye, L. & Walker, R. J. (1991). The pharmacology of cholinoceptors on the somatic muscle cells of the parasitic nematode, Ascaris suum. Journal of Experimental Biology 158, 509–30.CrossRefGoogle ScholarPubMed
Cowden, C., Sitihgorngul, p., Brackley, P., Guastella, J. & Stretton, A. O. W. (1993). Localization and differential expression of FMRFamide-like immunoreactivity in the nematode Ascaris suum. Journal of Comparative Neurology 333, 455–68.CrossRefGoogle ScholarPubMed
Cowden, C. & Stretton, A. O. W. (1993). AF2, an Ascaris neuropeptide: isolation, sequence and bioactivity. Peptides 14, 423–30.CrossRefGoogle ScholarPubMed
Cowden, C., Stretton, A. O. W. & Davis, R. E. (1989). AF1, a sequenced bioactive neuropeptide isolated from the nematode Ascaris suum. Neuron 2, 1465–73.CrossRefGoogle ScholarPubMed
Castillo, J.Del, De Mello, W. C. & Morales, T. (1963). The physiological role of acetylcholine in the neuromuscular system of Ascaris lumbricoides. Archives Internationales de physiologic 71, 741–57.CrossRefGoogle Scholar
Castillo, J.Del, De Mello, W. C. & Morales, T. (1964). Inhibitory action of γ-aminobutyric acid (GABA) on Ascaris muscle. Experientia 15, 141–3.CrossRefGoogle Scholar
Fleischer, S. & Inui, M. (1989). Biochemistry and biophysics of excitation–contraction coupling. Annual Review of Biophysics and Biophysical Chemistry 18, 333–64.CrossRefGoogle ScholarPubMed
Franks, C. J., Holden-Dye, L., Williams, R. G., Pang, F.-Y. & Walker, R. J. (1994). A nematode FMRFamide-like peptide SDPNFLRFamide (PF1) relaxes the dorsal muscle strip preparation of Ascaris suum. Parasitology 108, 229–36.CrossRefGoogle ScholarPubMed
Geary, T. G., Price, D. A., Bowman, J. W., Winterrowd, C. A., Mackenzie, C. D., Garrison, R. D., Williams, J. F. & Friedman, A. R. (1992). Two FMRFamide-like peptides from the free-living nematode Panagrellus redivivus. Peptides 13, 209–14.CrossRefGoogle ScholarPubMed
Holden-Dye, L., Krogsgaard-Larsen, P., Nielsen, L. & Walker, R. J. (1989). GABA receptors on the somatic muscle cells of the parasitic nematode Ascaris suum: stereoselectivity indicates similarity to a GABAA type recognition site. British Journal of Pharmacology 98, 841–51.CrossRefGoogle ScholarPubMed
Jarman, M. (1959). Electrical activity in the muscle cells of Ascaris lumbricoides. Nature, London 184, 1244.CrossRefGoogle Scholar
Johnson, C. D. & Stretton, A. O. W. (1985). Localization of choline acetyl transferase within identified motoneurones of the nematode Ascaris. Journal of Neuroscience 5, 1984–92.CrossRefGoogle Scholar
Johnson, C. D. & Stretton, A. O. W. (1987). GABA-immunoreactivity in the inhibitory motoneurones of the nematode Ascaris. Journal of Neuroscience 7, 223–35.CrossRefGoogle ScholarPubMed
Keating, C., Thorndyke, M. C., Holden-Dye, L., Williams, R. G. & Walker, R. J. (1994). The isolation of a FMRFamide–like peptide from the nematode Haemonchus contortus. Brain Research Association Abstracts 11, 16.11.Google Scholar
Martin, R. J., Thorn, P., Gration, K. A. & Harrow, I. D. (1992). Voltage-activated current in somatic muscle of the nematode parasite Ascaris suum. Journal of Experimental Biology 173, 75–90.CrossRefGoogle ScholarPubMed
Natoff, I. L. (1969). The pharmacology of the cholinoceptor in muscle preparations of Ascaris lumbricoides. British Journal of Pharmacology 37, 251–7.CrossRefGoogle ScholarPubMed
Pang, F.-Y., Holden-Dye, L. & Walker, R. J. (1992). The actions of acetylcholine and an FMRF-amide like peptide on the somatic muscle of the nematode Ascaris. British Journal of Pharmacology 107, 458P.Google Scholar
Rozhkova, E. K., Malyutina, T. A. & Shishov, B. A. (1980). Pharmacological characteristics of cholinoreception in the somatic muscles of the nematode Ascaris suum. General Pharmacology 11, 141–6.CrossRefGoogle ScholarPubMed
Stretton, A. O. W., Davis, R. E., Angstadt, J. D., Donmoyer, J. E. & Johnson, C. D. (1985). Neural control of behaviour in Ascaris. Trends in Neuroscience 8, 294–300.CrossRefGoogle Scholar
Walrond, J. P. & Stretton, A. O. W. (1985 a). Identification of excitatory and inhibitory motoneurones in the nematode Ascaris by electrophysiological techniques. Journal of Neuroscience 5, 1–8.CrossRefGoogle ScholarPubMed
Walrond, J. P. & Stretton, A. O. W. (1985 b). Excitatory and inhibitory activity in the dorsal musculature of the nematode Ascaris evoked by single dorsal excitatory motorneurons. Journal of Neuroscience 5, 16–22.CrossRefGoogle Scholar