Brain-midgut short neuropeptide F mechanism that inhibits digestive activity of the American cockroach, Periplaneta americana upon starvation

Peptides. 2012 Mar;34(1):135-44. doi: 10.1016/j.peptides.2011.10.028. Epub 2011 Nov 18.

Abstract

Immunohistochemical reactivity against short neuropeptide F (sNPF) was observed in the brain-corpus cardiacum and midgut paraneurons of the American cockroach, Periplaneta americana. Four weeks of starvation increased the number of sNPF-ir cells in the midgut epithelium but the refeeding decreased the number in 3h. Dramatic rises in sNPF contents in the midgut epithelium and hemolymph of roaches starved for 4 weeks were confirmed by ELISA. Starvation for 4 weeks reduced α-amylase, protease and lipase activities in the midgut of P. americana but refeeding restored these to high levels. Co-incubation of dissected midgut with sNPF at physiological concentrations inhibited α-amylase, protease and lipase activities. sNPF injection into the hemocoel led to a decrease in α-amylase, protease and lipase activities, whereas PBS injection had no effects. The injection of d-(+)-trehalose and l-proline into the hemocoel of decapitated adult male cockroaches that had been starved for 4 weeks had no effect on these digestive enzymes. However, injection into the hemocoel of head-intact starved cockroaches stimulated digestive activity. Injection of d-(+)-trehalose and l-proline into the lumen of decapitated cockroaches that had been starved for 4 weeks increased enzymes activities and suppressed sNPF in the midgut. Our data indicate that sNPF from the midgut paraneurons suppresses α-amylase, protease and lipase activities during starvation. Injection of d-(+)-trehalose/l-proline into the hemocoel of head-intact starved cockroach decreased the hemolymph sNPF content, which suggests that sNPF could be one of the brain factors, demonstrating brain-midgut interplay in the regulation of digestive activities and possibly nutrition-associated behavioral modifications.

MeSH terms

  • Animals
  • Brain
  • Digestion / drug effects
  • Digestive System / drug effects
  • Digestive System / enzymology
  • Digestive System / metabolism*
  • Enzyme Activation / drug effects
  • Immunohistochemistry
  • Lipase / metabolism
  • Male
  • Neuropeptides / chemistry
  • Neuropeptides / metabolism*
  • Neuropeptides / pharmacology*
  • Peptide Hydrolases / metabolism
  • Periplaneta / drug effects
  • Periplaneta / enzymology
  • Periplaneta / metabolism*
  • Starvation / enzymology
  • Starvation / metabolism*
  • alpha-Amylases / metabolism

Substances

  • Neuropeptides
  • neuropeptide F
  • Lipase
  • alpha-Amylases
  • Peptide Hydrolases