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 reg-ulated physiological events,we investigated if the second messenger cAMP would partic-ipate in the process of alkalinization in the abdominal midgut of female L.longipalpis.In midguts containing the indicator dye bromothymol-blue,cAMP stimulated the alkalin-ization 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-an-tiporter 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 in-dicated 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.

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

Laboratório de Fisiologia de Insetos Hematófagos,Departamento de Parasitologia//CB,Universidade Federal de Minas Gerais,Belo Horizonte,MG,Brazil

中国昆虫科学（英文版）

[1]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-.cAMP:A second messenger involved in the mechanism of midgut alkalinization in Lutzomyia longipalpis)[J].中国昆虫科学（英文版）,2022(04):1059-1070

alkalinization,Lutzomyia,longipalpis,ingest,midguts,alkalin,tiporter,Hematophagy,alkalinizing

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