Setting variable main in plot-function

Hi,

I am plotting the residuals of z like this

plot(resid(z))

and I want the title of the graph to be

main="Residuals from regression [name of regression]"

where in this case "z" is the name of the regression. Is there a way to 
automaticall put the name of the regression in the title, e.g if the 
regressions name changes to "y", the title changes accordingly?

Regards T Petersen