Journal of Comparative Physiology B

, Volume 169, Issue 8, pp 561–568

Electrophysiological and pharmacological characteristics of buccal smooth muscle of the pest slug Deroceras reticulatum

  • T. J. Wright
  • H. Huddart
ORIGINAL PAPER

DOI: 10.1007/s003600050256

Cite this article as:
Wright, T. & Huddart, H. J Comp Physiol B (1999) 169: 561. doi:10.1007/s003600050256
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Abstract

Buccal mass muscle of the pest slug Deroceras reticulatum was examined by conventional tension recording and the sucrose-gap electrophysiological technique. Elevated potassium salines induced dose-dependent depolarisations accompanied by tonic contractures with superimposed rapid twitch contractions. The latter were suppressed at over 40 mmol · l−1 external potassium, where depolarisation-induced inactivation of voltage-sensitive calcium channels may have occurred. Acetylcholine caused significant dose-dependent depolarisations and tonic contractures, while 5-hydroxy tryptamine induced lower depolarisations accompanied by phasic contractile activity superimposed on low level tonic force. Of the purines examined only guanosine triphosphate caused significant mechanical activity above a threshold of 0.1 μmol · l−1. The tetrapeptides inhibited buccal muscle spontaneous activity, but the related small cardioactive peptide B was weakly excitatory. The amino acids glutamate and gamma-aminobutyric acid were weakly excitatory on buccal muscle while the molluscicides metaldehyde and methiocarb disrupted normal mechanical activity of the feeding musculature. Acetylcholine and 5-hydroxytryptamine appear to have major roles in regulating feeding muscle activity, seemingly modulated by guanosine triphosphate and inhibited by phenylalanine-methionine-arginine-phenylalanine-NH2 and phenylalanine-leucine-arginine-phenylalanine-NH2.

Key words Acetylcholine Deroceras reticulatum FMRFamide FLRFamide GTP 5-Hydroxytryptamine Metaldehyde Methiocarb Sucrose Gap 
AbbreviationsACh acetylcholine 4-AP 4-aminopyridine FLRFamide phenylalanine-leucine-arginine-phenylalanine-NH2 FMRFamide phenylalanine-methionine-arginine-phenylalanine-NH2 GABA gamma aminobutyric acid GTP guanosine triphosphate 5-HT 5-hydroxytryptamine SCPB small cardioactive peptide B TEA tetraethyl ammonium chloride 

Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • T. J. Wright
    • 1
  • H. Huddart
    • 1
  1. 1.Department of Biological Sciences, I.E.N.S., Lancaster University, Lancaster LA1 4YQ, England, UK e-mail: H.Huddart@lancaster.ac.uk Tel.: +44-1524-65201; Fax: +44-1524-843854GB

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