Authors: Akçahan GEPDİREMEN, Sinan SÖNMEZ, Birkan YAKAN, Nur BANOĞLU, Dilek SADELER
Abstract: We have described a tremor model induced by 3,5 mg/kg chlorpromazine and 20 mg/kg pentobarbitone administered intraperitoneally in guinea pigs (frequency: 24/sec) and left handed cats (frequency: 12/sec). In this study; we produced similar tremors in rats by the same dosages of chlorpromazine and pentobarbitone administration intraperitoneally (frequency: 16-22sec). Then we examined the effects of GABA'ergic diazepam 2 µg/µl, dopaminergic amantadine 10 mg/µl and anticholinergic atropine 20 µg/µl to the Nucleus Caudatus, Globus Pallidus and Lateral Posterior Thalamic Nucleus stereotaxically, in order to show any alteration on the tremor's amplitudes or frequency in this model. In this way, we discussed the validity of this model for Parkinsonian tremors. In 9 groups, we had significant responses in the Globus Palllidus-diazepam group only in the mean scores of amplitudes by paired test. In comparison with the control measurement, for 1. minute; p<0.0005, 10. minute; p<0.0005, for 20.minute; p<0.0005 and for 30. minutep<0.05 were found in the Globus Pallidus-diazepam group. On the other hand, there was no significant difference of frequency of the tremors in any groups studied. Results of this study and former studies on the tremors induced by chlorpromazine and pentobarbitone indicate a reversible impairment in the basal ganglia's physiologic mechanisms in accordance with knowledge of the basal ganglia's anatomy and physiology, we have to consider that Subthalamic Nucleus, Dorsal Raphe Nucleus, Pedunculopontine Nucleus and Striato-pallidal inhibitory inputs to the Globus Pallidus may be a source of the tremors.
Keywords: Parkinsonism, GABA, Tremor, Stereotaxic, Basal Ganglia, Rats.