title: Knockdown of the adipokinetic hormone receptor increases feeding frequency in the two-spotted cricket Gryllus bimaculatus.
abstract: Adipokinetic hormone (AKH) is a peptide hormone that regulates the nutritional state in insects by supporting the mobilization of lipids. In the present study, we manipulated AKH signaling to evaluate how metabolic state regulates feeding in an orthopteran insect, the two-spotted cricket, Gryllus bimaculatus. This was accomplished by RNA interference (RNAi) targeting the receptor gene for AKH [G. bimaculatus AKHR (GrybiAKHR)]. We found that the knockdown of GrybiAKHR by AKHR-double-stranded RNA treatment decreased the levels of 1,2-diacylglycerol and trehalose in the hemolymph, whereas it increased the level of triacylglycerol in the fat body. In addition, the knockdown of GrybiAKHR enhanced starvation resistance and increased food intake. Furthermore, direct observation of GrybiAKHR(RNAi) crickets revealed that the knockdown of GrybiAKHR increased feeding frequency but did not alter meal duration, whereas locomotor activity decreased. The increased frequency of feeding by GrybiAKHR(RNAi) crickets eventually resulted in an increase of food intake. These data demonstrate that the regulation of the metabolic state by AKH signaling affects feeding frequency, probably through nutritional control.
authors.affiliation: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, the University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Konuma
authors.forename: Nobukatsu
authors.initials: N
authors.lastname: Morooka
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Nagasawa
authors.forename: Shinji
authors.initials: S
authors.lastname: Nagata
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002241:Carbohydrates / Q000737:chemistry; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics* / Q000502:physiology; D005247:Feeding Behavior; D005502:Food; D005786:Gene Expression Regulation; D006135:Gryllidae; D006458:Hemolymph / Q000378:metabolism; D008055:Lipids / Q000737:chemistry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D034622:RNA Interference; D018027:Receptors, Glucagon / Q000235:genetics* / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D014280:Triglycerides / Q000378:metabolism
chemical_list: C533337:AKHR protein, Drosophila; D002241:Carbohydrates; D018076:DNA, Complementary; D029721:Drosophila Proteins; D008055:Lipids; D010455:Peptides; D018027:Receptors, Glucagon; D014280:Triglycerides