From season 1 of Mighty Mouse: The New Adventures:
The Mighty Heroes had retired from crime fighting and opened an accounting agency. However, business has been next to non-existent. When Mighty Mouse comes in looking for assistance in solving a numbers related case, he recruits the aged heroes to help him foil Big Murray, whose scheme was a little bigger than he bargained for in "Heroes & Zeroes".
Then, in "Stress For Success", a restless Mighty Mouse seeks therapy.
Ralph Bakshi not only brought back his creations, the Mighty Heroes, but also a few other Terrytoons favorites, such as Deputy Dawg and Heckle & Jeckle, for guest appearances during the series. In addition to John Kricfalusi, the staff also included comics writer Doug Moench and future WB writer-producer Tom Minton. I think you can clearly see how Kricfalusi was able to develop Ren & Stimpy, based on his work here.