[Physical dependence of dihydroetorphine in mice and monkeys (author's transl)].

The ability of producing physical dependence of dihydroetorphine (DHE) was compared with that of morphine in mice and monkeys. In nalorphine-challenged mice the average numbers of jumping of the mice after DHE were less than those after morphine and etorphine (E). In 3 monkeys treated chronically with DHE abstinence syndrome failed to occur in nalorphine (5—8 mg/kg，sc) precipitated withdrawal tests during 108 days. A low degree of abstinence responses was seen in these monkeys in abrupt withdrawal tests. In contrast to this, severe abstinence syndrome was seen in other 3 morphine-dependent monkeys in both nalorphine precipitated and abrupt withdrawal tests. In 2 morphine-dependent monkeys (sc 50 mg/kg daily), their abstinence syndrome was suppressed for ⅟2——2⅟2 h by sc DHE 0.43—1.43 μg/kg, while sc morphine 5— 10 mg/kg could suppress their abstinence syndrome for more than 5 h. These data suggest that DHE produces a relatively low physical dependence in animals.