Acute subjective effects of dynorphin A(1-13) infusion in normal healthy subjects

Twelve healthy subjects with no history of substance abuse participated in a placebo-controlled single-blinded study of subjective response to acute i .v. administration of placebo and two doses of the natural shortened peptid e sequence of the rc-opioid agonist, dynorphin A(1-13) (low dose 120 mu g/k g, high dose 500 mu g/kg). Visual analog scales showed small but significan t negative mood and positive drug effect 10 min post infusion in the high d ose dynorphin compared to placebo infusion. The differences were no longer apparent at 30 min. These results show that dynorphin A(1-13), shown previo usly to have both neuroendocrine and modest analgesic effects, was well tol erated and produced modest transient subjective responses. (C) 1999 Elsevie r Science Ireland Ltd. All rights reserved.