Nicotine pretreatment diminished physostigmine-induced tremor in rats.
The aim of this work was evaluate the effects of acute and chronic nicotine pretreatment in the physostigmine-induced tremor in rats. Wistar male rats (3-4 months) were pretreated acutely with different nicotine doses (0, 0.1, 0.5 or 1.0 mg/kg) 10 min before physostigmine (0 and 0.5 mg/kg) treatment and then the tremor was registered by computerized system for 10 min. In another group, rats were pretreated acutely with 0.1 mg/kg of nicotine, recovered at different times (30 or 70 min), and were registered for physostigmine-induced tremor. Nicotine was also used chronically with equal doses for 8 days and recovered at 2, 7 or 21 days before registration of physostigmine-induced tremor. Tremor spectral analysis was performed for amplitude and frequency quantification. Our data show that the acute and chronic nicotine pretreatments alter physostigmine spectrum profile. Nicotine decreased physostigmine-induced tremor amplitude (p<0.05), without changing its tremor frequency. In acutely pretreated rats, recovery experiments showed return of physostigmine-induced tremor for control levels after 70 min, but after 8 days of chronic nicotine pretreatment recovery was delayed 3 weeks. The data analysis shows that acute or chronic nicotine administration can alleviate the physostigmine-induced tremor. Chronic nicotine pretreatment has a long tremor alleviation effect of physostigmine-induced tremor. Possible mechanisms involving the nicotine effects on the physostigmine-induced tremor are discussed.
da Fonseca
Adenilson de Souza
Ade S
Departamento de Farmacologia e Psicobiologia, Instituto de Biologia, Universidade do Estado do Rio de Janeiro, Av. 28 de Setembro, 87-Fundos, 20551-030, Rio de Janeiro, Brasil.
Santos
Ricardo
R
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005731:Ganglionic Stimulants / Q000494:pharmacology; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D010830:Physostigmine; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014202:Tremor / Q000139:chemically induced / Q000517:prevention & control*
D005731:Ganglionic Stimulants; D009538:Nicotine; D010830:Physostigmine