Distribution of Ionomotive Pumps and Control of Malpighian Tubule Secretion By Cyclic Nucleotides in the Black-Legged Tick, Ixodes Scapularis

Ticks have a hematophagous feeding strategy, and thus must regulate the uptake of excess ions and fluids during blood meal engorgement through ion and osmoregulation. The salivary glands are essential for tick hydromineral balance as they play a vital role in excretion of excess ions and fluids back to the host. In order to further characterize organs involved in ion and osmoregulation, we examined activity of Na+/K+ ATPase and V-type H+ ATPase, as these ionomotive pumps drive transport within the tick salivary glands and Malpighian tubules of other hematophagous insects. Na+/K+ ATPase and V-type H+ ATPase were immunolocalized to the midgut, salivary glands, Malpighian tubules, intestine and rectal sac. We examined secretion rates of Malpighian tubules when stimulated by cAMP and cGMP, which stimulated tubule secretion. Future studies should examine putative diuretic factors in the regulation of these organs in order to further characterize their contribution to hydromineral balance.