Neuropeptide stimulation of the nitric oxide signaling pathway in Drosophila melanogaster Malpighian tubules

Shireen A. Davies, Eric J. Stewart, Graham R. Huesmann, Nicholas J.V. Skaer, Simon H.P. Maddrell, Nathan J. Tublitz, Julian A.T. Dow

Research output: Contribution to journalArticlepeer-review


Activation of the nitric oxide (NO) and guanosine 3',5'-cyclic monophosphate (cGMP) signaling pathway stimulates fluid secretion by the Drosophila melanogaster Malpighian tubule. The neuropeptide cardioacceleratory peptide 2b (CAP(2b)) has been previously shown to stimulate fluid secretion in this epithelium by elevating intracellular cGMP levels. Therefore, it was of interest to investigate if CAP(2b) acts through NO in isolated tubules and thus presumably through stimulation of a tubule NO synthase (NOS). We show here by reverse-transcription polymerase chain reaction that Drosophila NOS (dNOS) is expressed in Malpighian tubules. Biochemical assays of NOS activity in whole tubules show that CAP(2b) significantly stimulates NOS activity. Additionally, fluid secretion and cyclic nucleotide assays show that CAP(2b)-induced elevation of intracellular cGMP levels and fluid secretion rates are dependent on the activation of a soluble guanylate cyclase. Treatment of tubules with a specific NOS inhibitor abolishes the CAP(2b)-induced rise in intracellular cGMP levels. These data indicate that CAP(2b) stimulates NOS and, therefore, endogenous NO production, which, in turn, stimulates a soluble guanylate cyclase. This is the first demonstration of stimulation of an endogenous NOS by a defined peptide in Drosophila.

Original languageEnglish (US)
Pages (from-to)R823-R827
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Issue number2 42-2
StatePublished - 1997
Externally publishedYes


  • Cardioacceleratory peptide 2b
  • Nitric oxide synthase

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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