Effect of Phenoxybenzamine and Hydergine on Urinary Gatechol Amines in Rats during Restraint

The technique of restraining rats in wire mesh was used to study urinary catechol amine excretion under stress. Rats restrained for 12 and 16 hrs excreted higher amounts of both A and NA than did free animals. Rats pre‐treated with phenoxybenzamine 10 mg/kg excreted more A and NA than did control animals, and these differences were pronounced during restraint. PBA appears to interfere with either binding of NA at the receptor site, or with its destruction, possibly in the liver or with re‐uptake. Hydergine 1 mg/kg did not alter the resting excretion of A or NA but increased the output of A in urine during restraint.