Neurobiology of peptidergic and aminergic neurons in insects

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Our research examines the functioning of the nervous system, using insects as experimental models. We are establishing the mechanisms by which the nervous system communicates; examining hormonal, synaptic, and modulatory mechanisms. In particular we are interested in the role of peptides and amines as neurohormones, released into the blood to co-ordinate activities of diverse groups of tissues; and as neuromodulators, modulating the ongoing activities of distinct pathways. We focus on identified neuropeptides and amines, and search for novel neuropeptides, concentrating on the medically-important bug, Rhodnius prolixus. This bug takes enormous blood meals from humans, and during the subsequent excretion of excess salts and water (diuresis), the parasite, Trypanosoma cruzi, is transmitted, resulting in Chagas' disease. We examine short term endocrinological events associated with feeding. In particular we are defining the input associated with feeding which results in elevations in haemolymph diuretic and antidiuretic hormones (all identified by us), examining the neurosecretory cells which release them, and their target sites (e.g. salivary glands, midgut, hindgut, Malpighian tubules, heart and epidermal cells). Progress in this area has been revolutionised because of the Rhodnius genome project. We can search the genome for neuropeptides and G-protein coupled receptors (GPCRs) based upon sequence homology from other organisms, clone their genes, synthesise the neuropeptides and examine their physiological effects on tissues associated with feeding, and upon expressed receptors.The information allows us to assess the neuroendocrinological relevance of these diuretic factors in overall feeding physiology. In addition to answering fundamental questions about nervous systems, this research lays the foundation for pest control strategies, targeting neuropeptides as lead compounds. The parasite is transmitted during diuresis, and so diuretic hormones actually control the transmission of Chagas' disease. Interfering with this process should interfere with the transmission of Chagas' disease, and therefore our recent discoveries of the diuretic and antidiuretic hormones is of some considerable importance.