Problems in getting LTP

[sharmakaushikp]

Hi everybody,

I am facing problems in getting LTP induced in my slices. I use a vibratome for preparing slices, 400 micron thick. Slices look healthy. Input-output curves are fine and as normal as before (like the days when I used to get good LTP). Stimulation electrodes are new and constant current stimulation is applied to Schaffer collateral pathway.. pH and osmolarity of aCSF are fine. I get good fEPSP responses when i record from stratum radiatum of hippocampal slices. Baseline gets stabilized easily for 30 minutes, after which I apply tetanic stimulation. Immediately after tetanic stimulation, post-tetanic poentiation (PTP) is very high, however, the slope values either decline to baeline within a few minutes, or the LTP induced is very low. I have tried all possible things to solve this problem. I have even used 4 tetanic trains and also theta burst protocols to get good LTP, but still I get only about 5-10% LTP in such conditions. Please help me by giving me some suggestions so that I may solve my problem.

Thanks.

- Kaushik

[Robert]

Hi,

I am working on synaptic plasticity for almost 10 years. Do you have the facebook account? I can explain to you all about it. But basically, the LTP paradigme that you are using is extremely high, and you probably killed the slice. Try to use a 100 Hz for 1 second only, or 100 for 1 second, 30 seconds apart. It should work. The other question is, what chamber do you use. Is it submerge or interface chamber? Lastly, do not use theta-burst stimulation.