Possible mechanisms of sustained tremor induction by nicotine in pilocarpine treated animals.
Alterations of steady state and metabolism of putative neurotransmitters were studied in the brain of rats with a sustained tremor evoked by nicotine and pilocarpine. The norepinephrine content in several brain regions was decreased whereas striatal dopamine was unchanged. Homovanillic acid concentrations were slightly increased, while 5-hydroxyindoleacetic acid concentrations were markedly increased. Pilocarpine alone increased the 5-hydroxytryptamine (5-HT) turnover rate at high ambient temperature (30-32 degrees C), but not at normal ambient temperature (22 +/- 2 degrees C), atropine partially blocked the increase of 5-HT turnover rate by pilocarpine. Pretreatment with p-chlorophenylalanine and hemicholinium-3 decreased the tremor intensity elicited by nicotine and pilocarpine . It is proposed that the increase of cholinergic function caused by nicotine and the activation of muscarinic receptors and the increase in 5-HT function caused by pilocarpine might be involved in the mechanisms of tremor induction by nicotine and pilocarpine.
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D003342:Corpus Striatum / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D010134:Fenclonine / Q000494:pharmacology; D006426:Hemicholinium 3 / Q000494:pharmacology; D006719:Homovanillic Acid / Q000378:metabolism; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism; D010862:Pilocarpine / Q000494:pharmacology*; D051381:Rats; D012701:Serotonin / Q000378:metabolism; D014202:Tremor / Q000139:chemically induced* / Q000378:metabolism
D010862:Pilocarpine; D006426:Hemicholinium 3; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D009538:Nicotine; D010134:Fenclonine; D004298:Dopamine; D009638:Norepinephrine; D006719:Homovanillic Acid