Effects of serotoninergic drugs on tremor induced by physostigmine in rats

S. Sarkar, B. Thomas, D. Muralikrishnan, K. P. Mohanakumar

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


We investigated the effects of various serotoninergic drugs and serotonin (5-HT) depletion on physostigmine-induced visible tremor in rats. Physostigmine (0.25-1.5 mg/kg) caused dose-dependent tremor, initiated at 3-5 min (latency decreases as dose increases) and lasted for 30-35 min. Serotonin agonists, 8-hydroxy-2-(di-n-propylamino) tetralin (2.5 mg/kg) and buspirone (5 mg/kg) augmented the tremor response caused by physostigmine. The 5-HT1/5-HT2 receptor antagonist, metergoline (1 mg/kg), and 5-HT2 blocker, cyproheptadine (10 mg/kg) significantly decreased the duration (40%) as well as intensity (45-50%) of physostigmine-tremor. The 5-HT(2a)/5-HT(2c) antagonist ritanserin (5 mg/kg) significantly reduced the duration (60%) without affecting the intensity of the tremor. In 5-HT depleted rats (p-chlorophenylalanine; 300 mg/kg, for 3 days), physostigmine failed to produce tremor. Interestingly, in these animals, administration of a non-specific 5-HT agonist, 5-methoxy-N,N-dimethyl tryptamine, caused high intensity tremor. These results suggest that presence of 5-HT at the pre-synaptic terminals is needed for the tremor response by physostigmine and the response is greatly mediated via post-synaptic 5-HT receptors. The overall data indicated a direct involvement of central 5-HT system in the cholinergic tremor induced by physostigmine. Copyright (C) 2000 Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)187-193
Number of pages7
JournalBehavioural Brain Research
Issue number2
StatePublished - May 2000


  • 5-HT involvement
  • Cholinergic tremor
  • Physostigmine
  • Serotonin depletion
  • Serotonin receptors
  • Tremor

ASJC Scopus subject areas

  • Behavioral Neuroscience


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