Inhomogeneous magnetization transfer (ihMT) is a promising technique for central nervous system imaging. Although ihMT signal is mostly observed in myelinated tissues, weaker ihMT signal may be revealed in other biological tissue. The fundamental relationship between the underlying NMR lineshape and the ihMT signal is still an open question. Here we investigate high resolution magic-angle spinning (HR-MAS) NMR to provide insight into the mechanisms underpinning line broadening of ihMT responsive samples. The resulting spectra evidence different dipolar Hamiltonian components contributing to line broadening and support ihMT as being dominated by inhomogeneous interaction in myelinated tissues.