Physiological and pharmacological investigation of the rectum function

Physiological and pharmacological characterizations of the larval Anopheles albimanus rectum

Millions of people infected and killed from malaria, which is vectored by mosquitoes. In order to control this communicable disease, normally we have to reduce the vector population, so it is critical to understand the process necessary for mosquito survival. Like all aquatic organisms, mosquito larvae have to adapt to a condition that can change significantly in ionic composition. The rectum is the major organ responsible for the regulation of ions in mosquito larvae. It can resorb essential ions and nutrients or excrete excess salts and waste products. The recta differ between mosquito species in structure, also in protein expression etc. however, these have not been characterized extensively.

Researchers from USA investigate the DAR cells (dorsal anterior rectal cells) and non-DAR cells (anterior ventral cells and all posterior cells) in anopheline larvae recta. Proton flux was measured at the basal membrane of larvae treated in varying salinities using self-referencing ion-selective microelectrodes. In addition, some pharmacological inhibitors were applied in these two cell types in the larvae to study the protein function. The results show that the basal membrane proton fluxes differ between DAR cells and non-DAR cells, indicating that protein function changes in different rearing conditions.

Finally, they gave out a model of rectal ion regulation that the non-DAR cells perform the resorptive function in saline water-reared larvae and the secretive function in freshwater-reared larvae. So, it seems may not so effective to reduce the anopheline larvae survival by changing the salinity.

Web-link: http://www.sciencedirect.com/science/article/B6VNH-5023KSG-1/2/d0ee40aebc49a7389861bb19cc6d9179

Keywords: DAR; Ion regulation; ISMs; Mosquito; Self-referencing

Reference: Kristin E. Smith et al. Physiological and pharmacological characterizations of the larval Anopheles albimanus rectum support a change in protein distribution and/or function in varying salinities, Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology, 2010, 157(1):55-62