Serotonin and feeding regulation in ants: an immunohistochemical analysis

FALIBENE, A; JOSENS, R; ROESSLER, W.

Congreso; XXVI Congreso Anual de la Sociedad Argentina de Investigación en Neurociencias; 2011

Serotonin (5-HT) plays an important role in the control and integration processes involved in feeding modulation in both vertebrates and  invertebrates. Pharmacological studies have demonstrated that this amine promotes anorexic effects on different insects. In the nectar-feeding ant Camponotus mus, 5-HT depresses feeding by reducing the efficiency per contraction of the sucking-pump muscles. In order to study the neuronal pathway relating 5-HT, feeding structures and its modulation, we analysed the presence of serotonergic neurons in the main ganglia involved in feeding. Furthermore, we studied 5-HT association with the sucking-pump muscles and the alimentary canal of these ants. Immunohistochemical studies all along the alimentary canal revealed 5-HT-like immunoreactive processes on the foregut (esophagus, crop and proventriculus), while the midgut and hindgut lacked 5-HT innervation. Although both the frontal and the subesophageal ganglion contained 5-HT immunoreactive cell bodies, direct serotonergic innervation in the sucking-pump muscles was absent. Altogether, the results indicate that 5-HT plays an important role in the regulation of food transport throughout the gut in ants and acts most likely via indirect regulation of the sucking pump activity.