Effects of intra-accumbens administration of dopamine agonists on stress-induced behavioural deficit.
The effect of post-footshock injections of (+)-amphetamine, the selective D2-receptor agonist quinpirole (LY 171555), and the D2-receptor antagonist metoclopramide, into the nucleus accumbens, on the formation of the open field deficit, has been studied in rats. Microinjections of (+)-amphetamine (10 micrograms) stimulated rat locomotor activity tested 5 min later, while quinpirole (10 micrograms) significantly inhibited animal motility in the test. The open field behaviour was not changed 24 h after injection of either drug. Amphetamine applied immediately after inescapable footshock did not modify stress-induced locomotor depression, when the rats' behaviour was examined 24 h later. On the other hand, post-shock injections of quinpirole significantly attenuated the long-term effects of the stressor, in the open field. Metoclopramide (10 micrograms) inhibited rat locomotor activity 5 min, but not 24 h, after local injection. Administration of a solution containing both quinpirole (10 micrograms) and metoclopramide (1 microgram) decreased motor activity of unstressed rats to a smaller degree than did quinpirole (10 micrograms) alone. Post-footshock injection of metoclopramide did not affect stress-induced hypomotility. It is concluded that the present data support the hypothesis that local depletion of brain dopaminergic stores causes some behavioural effects of stressors.
Płaźnik
A
A
Department of Pharmacology and Physiology of the Nervous System, Institute of Psychiatry and Neurology, Warszawa, Poland.
Stefański
R
R
Puciłowski
O
O
Kostowski
W
W
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D003913:Dextroamphetamine / Q000494:pharmacology; D015259:Dopamine Agents / Q000008:administration & dosage / Q000494:pharmacology*; D004597:Electroshock; D004873:Ergolines / Q000494:pharmacology; D008297:Male; D008787:Metoclopramide / Q000494:pharmacology; D008845:Microinjections; D009043:Motor Activity / Q000187:drug effects; D009714:Nucleus Accumbens / Q000033:anatomy & histology; D019257:Quinpirole; D051381:Rats; D011919:Rats, Inbred Strains; D012686:Septal Nuclei / Q000033:anatomy & histology; D013315:Stress, Psychological / Q000523:psychology*
D015259:Dopamine Agents; D004873:Ergolines; D019257:Quinpirole; D008787:Metoclopramide; D003913:Dextroamphetamine