Circling behavior in rats with 6-hydroxydopamine or electrolytic nigral lesions

Edgar T. Iwamoto, Horace H. Loh, E. Leong Way

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


Unilateral destruction of dopaminergic cell bodies in the substantia nigra zona compacta (SNC) was performed in rats using either electrocoagulation or chemical lesioning (6-hydroxydopamine, 6-OHDA). Neostriatal dopamine concentration ipsilateral to an electrolytic lesion was 34% of the contralateral side 2-3 weeks after operation; serotonin and noradrenaline brain levels were not altered. In contrast, dopamine and noradrenaline forebrain concentrations ipsilateral to a 6-OHDA lesion were 20 and 31%, respectively, of the contralateral side. After 6-OHDA, dopamine concentrations in the ipsilateral neostriatum were reduced to level below the sensitivity of the fluorometric assay; cortical, brainstem and neostriatal serotonin levels, on the other hand, were not altered after 6-OHDA. Ipsilateral circling behavior was elicited by d-amphetamine after electrolytic and chemical lesioning. In contrast, the direction of circling produced after apomorphine differed between the two lesion models: contralateral circling behavior was exhibited by 6-OHDA-lesioned rats, whereas ipsilateral circling was produced in animals with electrolytic lesions. Contralateral circling was induced in both lesion-type models by haloperidol or pimozide. S.c. atropine administration induced ipsilateral circling in rats with 6-OHDA lesions, wheras contralateral circling was observed after arecoline. Animals with electrolytic SNC lesions turn ipsilaterally after s.c. administrations of either arecoline ar atropine. The data indicate that the electrolytic and 6-OHDA circling behavior models represent two different neuropharmacological states and it is, therefore, suggested that comparisons of data obtained from models using different methods of lesioning be made with caution.

Original languageEnglish (US)
Pages (from-to)339-356
Number of pages18
JournalEuropean Journal of Pharmacology
Issue number2
StatePublished - Jun 1976

Bibliographical note

Funding Information:
This work was supportedin part by researchg rants from the National Institute of Mental Health (DA 00037) and DA 00564. Portions of this paperw ere presenteadt the 58th Annual Meetingo f the Federation of AmericanS ocietiesfo r ExperimentaBli ology, Atlantic City, NJ, April 7--12, 1974, and at the Western PharmacologSyo cietyM eetings,H onolulu,Hawaii, January 1975.


  • 6-OHDA SNC lesions
  • ACh agonists
  • ACh antagonists
  • Circling behavior model
  • DA agonists
  • DA antagonists
  • Electrolytic SNC lesions
  • Nigro-neostriatal pathway


Dive into the research topics of 'Circling behavior in rats with 6-hydroxydopamine or electrolytic nigral lesions'. Together they form a unique fingerprint.

Cite this