Many devices for obtaining cerebrospinal fluid (CSF) have been published. However, none of them allows the infusion and collection of CSF in a continuous or discontinuous base. The purpose for the design of this system is based on the possibility of injecting drugs of rapid or slow absorption (encapsulated in nanoparticles). Also useful, for studying the pharmacokinetics of drugs injected outside the cerebrospinal compartment (i.e. intraperitoneal), which can be followed over time by collecting small samples of CSF. Among the advantages of this system are the high yield of the CSF withdrawal (102.5±17 µL), without the presence of blood (around 99% of the rats tested (n=20)). Also, the survival of rats approaches around 75 % after a weekly CSF withdrawal repeated for one month (n=6). Finally, there was no need of a surgical procedure to expose the dura in the cisterna magna to withdraw CSF. The use of a stereotaxic device for securing the rat head allowed us to insert the collecting needle in a fixed place, without the guessing of other methods. Even though the use of this system appears to be expensive, it is worthwhile using it in pro of obtaining blood free CSF samples. In order to test this device, we assayed CSF for blood contamination, CSF protein determination and the pharmacokinetics of fluorescein in the CSF after the intravenous injection of the dye. Also, we studied the kinetic of infused minocycline into the CSF compartment. We can conclude that this device might become an indispensable tool in studies that involve manipulating the cerebrospinal compartment composition.

Key words: Cerebrospinal fluid, Collection of CSF, Infusion of drugs, Rat