This article describes deuterium NMR experiments on nematic single domains of vanadium pentoxide suspensions in D2O. Despite V2O5 volume fractions as low as 0.7%, the spectra are well-resolved quadrupolar doublets, characteristic of a uniaxial symmetry. We show that a simple model for the behavior of water in these suspensions accounts for the value of the splitting and for its concentration dependence. In this way, we obtain information on the interaction between water molecules and V2O5 colloidal ribbons. Then, the solvent (D2O) is used as a probe to study the reorientation time of the nematic phase. We show that this technique is sensitive enough to distinguish between reorientation through a transient instability or through a homogeneous rotation. In this latter case, we measure the characteristic time of reorientation tau in a magnetic field, as a function of volume fraction and temperature. We show a very strong temperature dependence of tau, which contrasts with the athermal phase diagram of this system.