We would like to start with mouse ICV administration, either direct using Hamilton or chronic using Alzet infusion kit. Regarding direct ICV infusion, I guess that volume and speed of injection need to be chosen carefully not to be too invasive for the mouse brain.
According to Alzet, total mouse CSF volume is 35 µl and turnover is 1.87 hour (ref unknown).
This means that natural flow is approx. 0.3 µl/min.
We currently are in the phase of investigating best-fit coordinates using colour dye. We now inject 1 µl 2.5% Evans Blue within 4 mins which is a normal speed according to above calculation (0.25 µl/min). However, the ventricular system fully turns blue in 4 mins (incl 4th ventricle) although a natural flow rate was achieved. It seems to me that the dye is pushed all over the system. I can imagine that, in case you want to target the immunological system, this volume and speed may be catastrophic.
I wonder whether there is no guideline reference for mouse ICV administration?
Any comments?