AUTHOR=Lange Angela , Alim Uzma , Vandersmissen Hans Peter , Mizoguchi Akira , Vanden Broeck Jozef , Orchard Ian 

TITLE=The Distribution and Physiological Effects of the Myoinhibiting Peptides in the Kissing Bug, Rhodnius Prolixus

JOURNAL=Frontiers in Neuroscience

VOLUME=6

YEAR=2012

URL=https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2012.00098

DOI=10.3389/fnins.2012.00098

ISSN=1662-453X

ABSTRACT=<p>The myoinhibiting peptides (MIPs), also designated as allatostatin-Bs or prothoracicostatic peptides in some insects, are neuropeptides that are characterized by two tryptophan (W) residues at the C-terminal, denoted as the W(X<sub>6</sub>)Wamide motif. They are believed to be the ancestral ligands for the <italic>Drosophila</italic> sex peptide (SP) receptor. Physiological functions of MIPs include the inhibition of contraction of insect visceral muscles, in addition to allatostatic and prothoracicostatic activities. The MIP precursor in <italic>Rhodnius prolixus</italic> encodes MIPs that have an unusual W(X<sub>7</sub>)Wamide motif. In the present study, MIP-like immunoreactivity was detected within neurons in the central nervous system and within the innervation to the salivary glands, hindgut, and female and male reproductive systems of adult <italic>R. prolixus</italic>. The effects of peptides with the unusual W(X<sub>7</sub>)Wamide motif (Rhopr-MIP-4) and with the typical W(X<sub>6</sub>)Wamide motif (Rhopr-MIP-7) were tested for physiological activity on <italic>R. prolixus</italic> hindgut contractions. Both peptides reduce the frequency and amplitude of hindgut contractions in a dose-dependent manner. In addition, both peptides activate the <italic>Drosophila</italic> SP receptor. The MIP/SP receptors are therefore activated by peptides with the unusual W(X<sub>7</sub>)Wamide motif.</p>