Dimemorfan prevents seizures induced by the L-type calcium channel activator BAY k-8644 in mice

Eun Joo Shin, Toshitaka Nabeshima, Phil Ho Lee, Won Ki Kim, Kwang Ho Ko, Jin Hyeong Jhoo, Wang Kee Jhoo, Joo Young Cha, Hyoung Chun Kim

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


A dextromethorphan (3-methoxy-17-methylmorphinan) analog, dimemorfan (3-methyl-N-methylmorphinan) that is not metabolized to dextrorphan [3-hydroxy-17-methylmorphinan, which induces phencyclidine (PCP)-like behavioral effects], attenuates maximal electroshock seizures. However, the pharmacological mechanism of action of dimemorfan remains to be determined. In this study, we assessed the locomotor activity mediated by these morphinans. Circling behavior was pronounced in mice treated with PCP or dextrorphan, while animals treated with dextromethorphan exhibited moderate behaviors. Dimemorfan did not show any significant behavioral effects. We used BAY k-8644 (an L-type Ca2+ channel agonist in the dihydropyridine class) to explore the effects of dextromethorphan and dimemorfan on the convulsant activity regulated by calcium channels. Intracerebroventricular injection of BAY k-8644 (37.5μg) significantly induced seizures in mice. As with dextromethorphan (6.25 or 12.5mg/kg), dimemorfan (6.25 or 12.5mg/kg) pretreatment significantly attenuated BAY k-8644-induced seizures in a dose-dependent manner. BAY k-8644-induced seizure activity paralleled increased expression of c-fos and c-jun, AP-1 DNA binding activity, and fos-related antigen immunoreactivity. Pretreatment with dextromethorphan or dimemorfan significantly attenuated the expression induced by BAY k-8644. Therefore, our results suggest that the anticonvulsant effects of dextromethorphan and dimemorfan are mediated, at least in part, via L-type calcium channel, and that dimemorfan is equipotent to dextromethorphan in preventing BAY k-8644-induced seizures, while it lacks behavioral side effects related to psychotomimetic reactions.

Original languageEnglish
Pages (from-to)267-276
Number of pages10
JournalBehavioural Brain Research
Issue number1-2
Publication statusPublished - 2004 May 5
Externally publishedYes


  • AP-1 DNA binding activity
  • BAY k-8644
  • Dextromethorphan
  • Dimemorfan
  • Phencyclidine-like behavior
  • c-fos
  • c-jun
  • fos-related antigen

ASJC Scopus subject areas

  • Behavioral Neuroscience


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