Effects of dynorphins on the movement spectra in mice

Abstract

The effects of intracerebral injection of dynorphin-(1-13)[D13] and dynorphin [dynorphin-(1-17), D17] on spontaneous locomotor activity were investigated by using a newly devised multi-dimensional behavioral analyser based on a capacitance system. With this equipment, nine different measures of behaviors exhibited by the mouse can be recorded. We found that 0.3 and 1 μg doses of D13 produced a significant increase in the linear locomotion recorded on the 1/1 and 1/2 counters within 15-30 min after injection. In addition, a 0.3 μg dose of. D13 significantly increased the grooming behavior recorded on the 1/16 counter, while within 15 min after injection, 0.3 and 1μg doses of D17 significantly increased the 1/8, 1/32, 1/128 and 1/256 sizes of movement consisting of circling and grooming behaviors. As the D13- and D17-induced behavioral effects were reversed by pretreatment with haloperidol(0. 025 mg/kg) and naloxoned mg/kg), respectively, the D13- and/or Dl7-induced increases in linear locomotion, circling and grooming are probably r.ediated by both dopamine and opiate receptors in the brain. Additionally, the behavioral effects of D13 might be iifferet from those of D17.