Dielectric relaxation behavior was examined for solutions of a series of cis-polyisoprene (PI) chains having almost identical molecular weights (M congruent to 48K) but differently inverted type-A dipoles parallel along the chain contour. The solvent used was a dielectrically inert butadiene oligomer of M = 0.7K that was a moderately good solvent for the PI chains. Global motion of the dipole-inverted PI chains induced prominent dielectric relaxation at low frequencies, and the dielectric loss (epsilon ") curves changed their shape (frequency dependence) with increasing PI concentration c(PI) : At c(PI) smaller than the overlapping threshold c* the epsilon " curves were rather sharp and reasonably close to the prediction of the Tschoegl model considering both hydrodynamic and excluded-volume interactions, while for c(PI) > c* the distribution became considerably broader than that predicted from the Rouse/Zimm/Tschoegl and reptation models. These dielectric changes were quite similar to those found in previous studies for PI solutions in Isopar-G and heptane. The shape of the epsilon " curves reflected distribution of both relaxation times and intensities of dielectric modes, while those times and intensities were separately determined by characteristic times tau(p) and integrated eigenfunctions F-p(n) for eigenmodes of a local correlation function, C(n,t;m) = [(u(n,t) . u(m,0)]/[(u(2)], with u(n,t) being the nth bond vector at time t. For detailed examination of the above dielectric changes with c(PI), the epsilon " data of the dipole-inverted PI chains were analyzed to evaluate F-p(n) and tau(p) (for the eigenmode index p = 1-3). At c(PI) less than or equal to c*, tau(p) were almost proportional to p(-1.65) and F-p(n) were nearly sinusoidal with respect to the segment location n. These results were in reasonable agreement with the Tschoegl model. With increasing c(PI) > c*, tau(p) became almost proportional to p(-2) while F-p(n) became nonsinusoidal. This p dependence of tau(p) was still in close agreement with the Rouse and/or reptation models, but the n dependence of F-p(n) was considerably different. This result indicated that the broadening of the epsilon " curves with c(PI) was essentially due to changes in the eigenfunctions, not due to changes in the p dependence of tau(p) (relaxation time span). Changes of F-p(n) with c(PI) were discussed in relation to coupling of motion pf chains being overlapped at c(PI) > c*.