A pharmacological study of cocaine activity in planaria

G. Palladini, S. Ruggeri, F. Stocchi, M. F. De Pandis, G. Venturini, V. Margotta

Research output: Contribution to journalArticlepeer-review


Planaria has been proposed as a suitable research model in neurobiology because of its relatively simple organization. Dopaminergic agonists induce in this flatworm typical hyperkinesias that can be antagonized by dopaminergic blocking agents. The neurochemical basis of the effects of cocaine invertebrates has not been fully elucidated, but the inhibition of catecholamine reuptake at a presynaptic level seems to play an important role. In this study we analyzed the involvement of the dopaminergic system in the mechanism of action of cocaine in planaria. The dose-related effects of cocaine on planaria motility and the response to cocaine treatment associated with the administration of specific D1 or D2 dopamine agonists and antagonists were investigated. The effects of reuptake inhibitors on cocaine activity were also studied. Planaria specimens treated with low doses of cocaine become motionless, whereas high doses induce a typical behavioural response, identical to the response induced by specific D2 agonists. This response is inhibited by a D2 selective blocking agent. Nomifensine, a specific dopamine reuptake inhibitor, induces a mixed D1/D2 response. The results of these expertments are discussed, also in relation with the conservation of dopaminergic receptors during evolution. Copyright (C) 1996 Elsevier Science Inc.

Original languageEnglish
Pages (from-to)41-45
Number of pages5
JournalComparative Biochemistry and Physiology - C Pharmacology Toxicology and Endocrinology
Issue number1
Publication statusPublished - Sep 1996


  • cAMP
  • cocaine
  • DA D1 receptors
  • DA D2 receptors
  • dopamine agonists
  • dopamine antagonists
  • invertebrates
  • planaria

ASJC Scopus subject areas

  • Pharmacology
  • Immunology


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