Showing frequency and amplitude after doing an FFT on a signal
A strong amplitude response at 0 Hz simply means that you have a very strong DC offset. In other words, it just means that the mean of your signal is not 0. 

If this is the only problem you have, then all you really need to do, is remove the mean of your signal. In other words:

vp_sig_orig = vp_sig_orig - mean(vp_sig_orig);