Pharmacological analysis of dopamine modulation in the drosophila melanogaster larval heart

Josh S. Titlow, Jenna M. Rufer, Kayla E. King, Robin L. Cooper

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Dopamine (DA) and other neurotransmitters affect nonneuronal tissues in insects by circulating in the hemolymph. In several organisms, DA has been shown to modulate distinct aspects of cardiac function but the signal transduction pathways that mediate dopaminergic effects on the heart are not well characterized. Here, we used a semiintact Drosophila melanogaster larva preparation and drugs targeting DA receptors and canonical second messenger pathways to identify signaling cascades that mediate the effect of DA on a myogenic heart. DA has a positive chronotropic effect that is mimicked by SKF38393 (type-1 DA receptor agonist) and quinpirole (type-2 DA receptor agonist). SCH23390 and spiperone (type-1 and type-2 DA receptor antagonists) are moderately effective at inhibiting DA’s effect. An adenylate cyclase inhibitor (SQ,22536) is also effective at blocking the stimulatory effect of DA but the drug has its own dose-dependent effect. Activation of protein kinase C with a diacylglycerol analog has a stimulatory effect on heart rate (HR). These results suggest that (1) both DA receptor subtypes are expressed in third instar larva cardiac myocytes to increase HR in response to rising levels of DA in the hemolymph, and (2) canonical second messenger pathways modulate HR in D. melanogaster larvae. Having these disparate signaling cascades converge toward a common modulatory function appears redundant, but in the context of multiple cardioactive chemicals this redundancy is likely to increase the fidelity of signal transduction.

Original languageEnglish
Article numbere00020
JournalPhysiological Reports
Volume1
Issue number2
DOIs
StatePublished - Jul 2013

Bibliographical note

Publisher Copyright:
© 2013 The Authors.

Keywords

  • Dopamine
  • Drosophila melanogaster
  • Heart
  • Larva
  • Pharmacology

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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