A novel type of implantable and programmable infusion pump for small laboratory animals.

INTRODUCTION The iPRECIO (Primetech Corporation, Tokyo, Japan) is a new form of pump for infusing small laboratory animals. The key features of the iPRECIO are that it can be implanted within the animal, it is refillable, and it is programmable. The infusion start-points and end-points are adjustable, infusion rate can be altered, and the infusion solution can be changed after the pump is implanted. In order to confirm the precision of the iPRECIO, in vivo and in vitro experiments were employed. METHODS In the in vitro experiment, at the excretion rate of 1 microl/h for 336 h, 15 microl/h for 96 h, and 30 microl/h for 120 h, the decrease in each pump weight was used to estimate the actual excretion volume. In the in vivo experiments, the iPRECIO was chronically implanted in rats, angiotensin II was infused, and arterial pressure (AP) was monitored. RESULTS In the in vitro experiment, the volume of solution excreted from the pump increased with time, and the volume excreted matched the programmed volume. The infusion rate also changed at the scheduled time. In the in vivo experiment, AP increased and decreased on schedule, and a dose-dependent pressor response to angiotensin II occurred. Furthermore, after exchanging saline with angiotensin II, AP increased and decreased on schedule. DISCUSSION Present data of the in vitro and in vivo experiments indicates that the iPRECIO worked precisely, making it suitable for a variety of experiments involving small laboratory animals.