Cindy,
We use SMA  from Dako (M0851) at 1:1000 - this has been good, clean reliable
antibody for us.  Works on both Rat and Human.
FYI - For mouse we use SMA-EPOS. Also from Dako (U7033). Super Product!

Sorry I can't help you with Collagen IV.  Ours works so far only on human.
I would be interested in the info if you do get advice on an Antibody for
Rat and/or Mouse.

Please feel free to E-mail me directly if you need any more information on
SMA.

Chris Rogahn
crogahn@prius.jnj.com