  We study the action of operators on tent spaces such as maximal operators,
Calder{\'o}n-Zygmund operators, Riesz potentials. We also consider singular
non-integral operators. We obtain boundedness as an application of
extrapolation methods in the Banach range. In the non Banach range, boundedness
results for Calder{\'o}n-Zygmund operators follows by using an appropriate
atomic theory. We end with some consequences on amalgalm spaces.
