  We estimate the resonance coupling strength $f_{RN\omega}$ and $f_{RN\rho}$
from a Vector Meson Dominance (VMD) analysis. The isoscalar and isovector part
of the photon coupling are obtained separately from helicity amplitudes. The
reliability of this approach is tested by comparing VMD predictions for
$f_{RN\rho}$ with values obtained from fitting the hadronic decay widths into
$N \rho$. A reasonable agreement is found, but VMD tends to underestimate the
coupling constants. In order to confirm consistency with experimental data, we
calculate the cross-sections for photon-and pion induced reactions within a
{\it Breit-Wigner} model. Finally, we study how the properties of $\omega$
mesons in nuclear matter are affected from the excitation of resonance-hole
loops. For an $\omega$ at rest, we find a broadening of about 40 MeV, while at
higher momenta the effect of resonance excitations is reduced.
