Deb how are his respirations? Normal for a cat would be about 30 breaths per minute, if you are counting higher than that, he could be in pain. Rapid shallow breathing is also an indication of heat stroke, if it lasts over 15 minutes in length please call the vet and get him in. Sorry, I wasn't home this morning and just now saw this. Hope Joey, or Squirt is okay by now.
He's ok, MA. This was in the car on the way home from the vet. He was super-stressed abnd probably hot as well. His breathing was pretty rapid and shallow. He was ok once he got into the house and calmed himself down. By the time I posted this, he was fine, but I was just wondering about the open mouth thing. It resembled the way a dog pants.
The open mouthed breathing in cats is sometimes due to something called the Flehming response, which is a special way of smelling. There are smelling organs in the roof of the cats' mouths. When they really, really want to smell something, they often open their mouths and suck the air to smell/taste it (molecules of the things being smell are in the air). My cats tend to do it when they are in the car also. Lots of new strange smells on the road.