Possible mechanism of 5-methoxy-N,N-dimethyltryptamine-induced turning behaviour in DRN lesioned rats.
5-Methoxy-N,N-dimethyltryptamine (5-MeODMT) (7.5 mg/kg SC) caused a contralateral turning in rats with a unilateral lesion of the dorsal raphe nucleus (DRN). This turning behaviour was blocked by pretreatment with putative 5-HT antagonists, methysergide, cyproheptadine and cinanserin. The peripheral 5-HT antagonist, xylamidine, also prevented the response to 5-MeODMT. Of the other neurotransmitter antagonists, only haloperidol was active, hyoscine, picrotoxin, naloxone and strychnine were ineffective. Pretreatment with alpha-methyl-p-tyrosine (alpha-MT) also significantly reduced the turning response to 5-MeODMT. These results indicate that a central dopaminergic system is involved in 5-MeODMT-induced turning behaviour. This suggestion is supported by the finding that an ipsilateral turning in response to 5-MeODMT was observed in the rats with additional 6-hydroxydopamine (6-OHDA) lesions of the medial forebrain bundle (MFB). The possible mechanisms by which 5-MeODMT induced turning in DRN lesioned rats are discussed.
D000818:Animals; D001933:Brain Stem / Q000502:physiology*; D002928:Cinanserin / Q000494:pharmacology; D003533:Cyproheptadine / Q000494:pharmacology; D004336:Drug Antagonism; D008297:Male; D008732:Methoxydimethyltryptamines / Q000494:pharmacology*; D008784:Methysergide / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects*; D009068:Movement / Q000187:drug effects; D011903:Raphe Nuclei / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000031:analogs & derivatives*
D008732:Methoxydimethyltryptamines; D003533:Cyproheptadine; D012701:Serotonin; D002928:Cinanserin; D008784:Methysergide