Immunohistological localization of regulatory peptides in the midgut of the female mosquitoAedes aegypti

Abstract

The midgut of the female mosquito Aedes aegypti was studied immunohistologically with antisera to various regulatory peptides. Endocrine cells immunoreactive with antisera to perisulfakinin, RFamide, bovine pancreatic polypeptide, urotensin 1, locustatachykinin 2 and allatostatins A1 and B2 were found in the midgut. Perisulfakinin, RFamide and bovine pancreatic polypeptide all react with the same, about 500 endocrine cells, which were evenly distributed throughout the posterior midgut, with the exception of its most frontal and caudal regions. In addition, these antisera recognized three to five neurons in each ingluvial ganglion and their axons, which ran longitudinally over the anterior midgut, as well as axons innervating the pyloric sphincter. The latter axons appear to be derived from neurons located in the abdominal ganglia. Antisera to two different allatostatins recognized about 70 endocrine cells in the most caudal area of the posterior midgut and axons in the anterior midgut whose cell bodies were probably located in either the brain or the frontal ganglion. Antiserum to locustatachykinin 2 recognized endocrine cells present in the anterior midgut and the most frontal part of the posterior midgut, as well as about 50 cells in the most caudal region of the posterior midgut. Urotensin 1 immunoreactivity was found in endocrine cells in the same region as the perisulfakinin-immunoreactive cells, but no urotensin-immunoreactive axons were found in the midgut. Double labeling experiments showed that the urotensin and perisulfakinin immunoreactivities were located in different cells. Such experiments also showed that the locustatachykinin and allatostatin immunoreactivities in the most caudal area of the posterior midgut were present in different cells. No immunoreactivity was found in the mosquito midgut when using antisera to corazonin, allatropin or leucokinin IV. Since these peptides have either been isolated from, or can reasonably be expected to be present in mosquitoes, it was concluded that these peptides are not present in the mosquito midgut.

Immunostaining for allatotropin and allatostatin-A and -C in the mosquitoes Aedes aegypti and Anopheles albimanus

“…Immunoreactivity against AS-A has been previously described in a specific group of endocrine midgut cells in female A. aegypti (Veenstra et al 1995). We have found a similar result in A. albimanus.…”

“…Immunostaining of AS-A has been found in various tissues of several insects, including endocrine midgut cells of A. aegypti (Veenstra et al 1995). These AS-A endocrine cells are "open type" cells.…”

Novel antennal lobe substructures revealed in the small hive beetle Aethina tumida

“…It was raised in rabbits against locustatachykinin-2 (Lom-TK II, APLSGFYGVRamide) glutaraldehyde-conjugated to bovine thyroglobulin (Veenstra et al, 1995). The antiserum is known to detect tachykinin-related peptides (TKRPs, consensus sequence FXGXRamide) in other insects as well (e.g.…”

Allatostatin A-like immunoreactivity in the nervous system and gut of the larval midge, Chironomus riparius (Meigen): Modulation of hindgut motility, rectal K+ transport and implications for exposure to salinity

“…In particular, the ASTs have been shown to inhibit contractions of visceral muscle including the foregut and hindgut (Lange et al, 1993;Sarkar et al, 2003;Predel et al, 2001;Matthews et al, 2008), and have been localized to endocrine cells of the gut (Veenstra et al, 1995;Veenstra, 2009;Reichwald et al, 1994;Robertson and Lange, 2010), suggesting that they may have a role in feeding and digestion. In the cockroach, ASTs have been shown to decrease food consumption (Aguilar et al, 2003).…”