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Innervation of dromyosuppressin (DMS) immunoreactive processes and effect of DMS and benzethonium chloride on the Phormia regina (Meigen) crop
Author(s) -
Richer Sarah,
Stoffolano John G.,
Yin ChihMing,
Nichols Ruthann
Publication year - 2000
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/(sici)1096-9861(20000522)421:1<136::aid-cne8>3.0.co;2-c
Subject(s) - biology , crop , zoology , ecology
Antibody to the dipteran myosuppressin peptide, dromyosuppressin, TDVDHVFLRFamide, stained cells and fibers in the brain, optic lobes, subesophageal ganglion, and thoracico‐abdominal ganglion of the blow fly, Phormia regina (Meigen). Dromyosuppressin‐like immunoreactive fibers were detected in the cardiac recurrent nerve, hypocerebral ganglion/corpora cardiaca complex, crop duct, and crop. In order to explore the mechanisms involved in regulating crop movement, we established an in vitro bioassay. The basal rate of crop movement was 50.8 ± 1.5 contractions per minute. Application of 1 μl of saline to the crop did not significantly affect the rate of movement compared to the basal rate (46.1 ± 1.1 contractions per minute, P < 0.05). Application of 1 μl 10 ‐6 M dromyosuppressin or 1 μl 10 ‐3 M benzethonium chloride to the crop slowed the rate to 2.2 ± 0.2 and 6.1 ± 0.7 contractions per minute, respectively. Although other data have previously been interpreted to suggest that dipteran crop contractions do not include a neural component, the neuropeptide dromyosuppressin affected P. regina crop motility. Innervation of the crop and crop duct by dromyosuppressin immunoreactive processes that originated in the central nervous system and the effect of dromyosuppressin on crop muscle contractions suggest that dromyosuppressin is released locally to modulate crop contractions and that crop motility is under neural regulation. Myosuppressins isolated from numerous insects have a high degree of structure identity and reduce spontaneous muscle contractions of the hindgut, oviduct, and heart. Benzethonium chloride, previously identified as a myosuppressin agonist on the cockroach hindgut and locust oviduct, mimicked the effect of dromyosuppressin on the crop. This suggests that structural requirements for myosuppressin receptor binding in the cockroach hindgut, locust oviduct, and fruit fly crop are similar. J. Comp. Neurol. 421:136–142, 2000. © 2000 Wiley‐Liss, Inc.