Villalobos-Sambucaro María José, Lorenzo-Figueiras Alicia Nieves, Riccillo Fernando Luis, Diambra Luis Anibal, Noriega Fernando Gabriel, Ronderos Jorge Rafael
Cátedra Histología y Embriología Animal (FCNyM-UNLP), La Plata, Argentina; Centro Regional de Estudios Genómicos (CREG-UNLP), La Plata, Argentina.
Departamento de Biodiversidad y Biología Experimental (IBBEA, FCEyN-UBA), Buenos Aires, Argentina.
PLoS One. 2015 Apr 21;10(4):e0124131. doi: 10.1371/journal.pone.0124131. eCollection 2015.
Haematophagous insects can ingest large quantities of blood in a single meal and eliminate high volumes of urine in the next few hours. This rise in diuresis is possible because the excretory activity of the Malpighian tubules is facilitated by an increase in haemolymph circulation as a result of intensification of aorta contractions combined with an increase of the anterior midgut peristaltic waves. It has been previously described that haemolymph circulation during post-prandial diuresis is stimulated by the synergistic activity of allatotropin (AT) and serotonin in the kissing bug Triatoma infestans; resulting in an increase in aorta contractions. In the same species, AT stimulates anterior midgut and rectum muscle contractions to mix urine and feces and facilitate the voiding of the rectum. Furthermore, levels of AT in midgut and Malpighian tubules increased in the afternoon when insects are getting ready for nocturnal feeding. In the present study we describe the synergistic effect of AT and serotonin increasing the frequency of contractions of the aorta in Rhodnius prolixus. The basal frequency of contractions of the aorta in the afternoon is higher that the observed during the morning, suggesting the existence of a daily rhythmic activity. The AT receptor is expressed in the rectum, midgut and dorsal vessel, three critical organs involved in post-prandial diuresis. All together these findings provide evidence that AT plays a role as a myoregulatory and cardioacceleratory peptide in R. prolixus.
吸血昆虫一次进食可摄取大量血液，并在接下来的几个小时内排出大量尿液。利尿作用的增强是可能的，因为马尔皮基氏小管的排泄活动因主动脉收缩加剧以及中肠前段蠕动波增加导致血淋巴循环增强而得到促进。先前已有描述，在侵扰锥蝽中，餐后利尿期间血淋巴循环受到促前胸腺激素（AT）和血清素协同作用的刺激，导致主动脉收缩增加。在同一物种中，AT刺激中肠前段和直肠肌肉收缩，以混合尿液和粪便并促进直肠排空。此外，当昆虫准备夜间进食时，下午中肠和马尔皮基氏小管中的AT水平会升高。在本研究中，我们描述了AT和血清素对致倦库蚊主动脉收缩频率增加的协同作用。下午主动脉收缩的基础频率高于上午观察到的频率，表明存在每日节律性活动。AT受体在直肠、中肠和背血管中表达，这三个关键器官参与餐后利尿。所有这些发现共同提供了证据，表明AT在致倦库蚊中作为一种肌肉调节和心脏加速肽发挥作用。
