Tolerance to cadmium in the abdominal stretch response: a comparative study of cadmium and acetic acid

The intraperitoneal injection of cadmium (Cd) in mice produces a characteristic abdominal stretch response similar to that observed with acetic acid. Morphine, clonidine, and tripelennamine ED50 values were the same for inhibition of the response to Cd and to acetic acid. The ED50 values for aspirin and indomethacin were lower against the Cd than the acetic acid response. On repeated injections, Cd did but acetic acid did not produce tolerance to itself. Furthermore, the mice made tolerant to Cd were not cross-tolerant to acetic acid, but the acetic-acid-treated mice were cross-tolerant to Cd. These results suggest that Cd and acetic acid may produce the stretch response through different mechanisms, and the Cd-induced response might serve as a screening test for aspirin-like agents.