TY - JOUR

T1 - Electrophysiological and pharmacological characteristics of buccal smooth muscle of the pest slug Deroceras reticulatum.

AU - Wright, T. J.

AU - Huddart, H.

PY - 1999/12

Y1 - 1999/12

N2 - 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.

AB - 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.

KW - Acetylcholine - Deroceras reticulatum - FMRFamide - FLRFamide - GTP 5-Hydroxytryptamine - Metaldehyde - Methiocarb - Sucrose Gap

U2 - 10.1007/s003600050256

DO - 10.1007/s003600050256

M3 - Journal article

VL - 169

SP - 561

EP - 568

JO - Journal of Comparative Physiology B

JF - Journal of Comparative Physiology B

SN - 0174-1578

IS - 8

ER -