Distribution and characterization of allatostatin in the central nervous system of the hematophagous insect Triatoma infestans (Hemiptera: Reduviidae)

GALVANI GERÓNIMO L; DE BENEDICTIS MARIANA; FRUTTERO LL; CARLINI CR; CANAVOSO LE; SETTEMBRINI BEATRIZ P

Amsterdam

Simposio; VII International Symposium On Insect Molecular Biology; 2014

Center for Insect Science

Allatostatins (ALAs) were first identified in insects for its role in the inhibition of juvenile hormone synthesis in the corpora allata. ALA was reported in many insect species as well as in other invertebrate taxa. Three types of ALAs differing in the C-terminal region of the peptide constitute the ALA family. The objective of the present work was to study the distribution of ALA in the central nervous system of Triatoma infestans, the main insect vector of Chagas´ disease, as well as its coexistence with other neuroactive molecules. Distribution of ALA in the brain was analyzed by immunocytochemistry using an antibody directed against the amino acid sequence, AYSYVSEYKALPVYNFLG-NH2. Results showed that in the protocerebrum, ALA-like immunoreactive somata were present in the calices of the mushroom bodies and in the pars intercerebralis. The antennal lobe contained numerous immunopositive somata and the glomeruli showed immunostained varicose fibers. Stained cell bodies were also detected in the antennal mechanosensory and motor center. In addition, tandem mass spectrometry (MS/MS) was performed sampling the brain and ganglia of the central nervous system. Acquired MS/MS spectra were processed and searches were performed against the NCBI database (Insecta, taxid: 50557), confirming the presence of ALA in the sample. The finding of ALA-like immunoreactivity in areas related to olfactory behaviour prompted us to analyze the distribution of nitric oxide synthase (NOS), the enzyme which catalyzes the formation of NO, a molecule with a recognized function in insect olfaction and chemoreception. The possible coexistence of both markers was evaluated by incubating brain sections with the ALA antiserum followed by NADPH-diaphorase histochemical reaction. It was found that both markers coexisted in specific somata of the antennal lobe. The distribution of ALA in the central nervous system of T. infestans suggests neuroendocrine and neurotransmitter roles of the neuropeptide related to olfactory behavior.