cAMP:A second messenger involved in the mechanism of midgut alkalinization in Lutzomyia longipalpis  

作　　者：Denise Barguil Nepomuceno Grasielle Caldas D’Ávila Pessoa Leonardo Barbosa Koerich Marcos Horácio Pereira Mauricio Roberto Viana Sant'Anna Ricardo Nascimento Araújo Nelder Figueiredo Gontijo 

机构地区：[1]Laboratório de Fisiologia de Insetos Hematófagos,Departamento de Parasitologia/ICB,Universidade Federal de Minas Gerais,Belo Horizonte,MG,Brazil

出　　处：《Insect Science》2022年第4期1059-1070,共12页昆虫科学（英文版）

基　　金：This work was supported by Fundacao de Amparo a Pesquisa do Estado de Minas Gerais(FAPEMIG),Conselho Nacional de Desenvolvimento Cientifico e Teenologico(CNPq),Instituto Nacional de Ciencia e Teenologia-Entomologia Molecular(INCT-EM),and Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior(CAPES).

摘　　要：The sand fly Lutzomyia longipalpis is the main vector of Leishmania infantum in the Americas.Female sand flies ingest sugar-rich solutions and blood,which are digested in the midgut.Digestion of nutrients is an essential function performed by digestive enzymes,which require appropriate physiological conditions.One of the main aspects that influence enzymatic activity is the gut pH,which must be tightly controlled.Considering second messengers are frequently involved in the coordination of tightly regulated physiological events,we investigated if the second messenger cAMP would participate in the process of alkalinization in the abdominal midgut of female L.longipalpis.In midguts containing the indicator dye bromothymol-blue,cAMP stimulated the alkalinization of the midgut lumen.Through another technique based on the use of fluorescein as a pH indicator,we propose that cAMP is involved in the alkalinization of the midgut by activating HCO3-transport from the enterocyte's cytoplasm to the lumen.The results strongly suggested that the carrier responsible for this process would be a HCO3−/Cl−antiporter located in the enterocytes’apical membrane.Hematophagy promotes the release of alkalinizing hormones in the hemolymph;however,when the enzyme adenylyl cyclase,responsible for cAMP production,was inhibited,we observed that the hemolymph from blood-fed L.longipalpis’females did not stimulate midgut alkalinization.This result indicated that hormone-stimulated alkalinization is mediated by cAMP.In the present study,we provide evidences that cAMP has a key role in the control of intestinal pH.

关 键 词：abdominal midgut ALKALINIZATION CAMP HCO_(3)^(-)/Cl^(-)antiport HORMONE Lulcomyia longipalpis 

分 类 号：Q78[生物学—分子生物学]