title: Brain-midgut short neuropeptide F mechanism that inhibits digestive activity of the American cockroach, Periplaneta americana upon starvation.
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.
authors: Kobe University, Kobe, Japan.
authors: Azam
authors: A
authors: Mikani
authors: Qiu-Shi
authors: QS
authors: Wang
authors: Makio
authors: M
authors: Takeda
mesh_terms: D000818:Animals; D001921:Brain; D004063:Digestion / Q000187:drug effects; D004064:Digestive System / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D007150:Immunohistochemistry; D008049:Lipase / Q000378:metabolism; D008297:Male; D009479:Neuropeptides / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D010447:Peptide Hydrolases / Q000378:metabolism; D010526:Periplaneta / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D013217:Starvation / Q000201:enzymology / Q000378:metabolism*; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D009479:Neuropeptides; C076101:neuropeptide F; D008049:Lipase; D000516:alpha-Amylases; D010447:Peptide Hydrolases