Physiol. Res. 51 (Suppl. 1): S67-S76, 2002

 


Striatal Level of Regulation of Learned Forepaw Movements in Rats

I. A. ZHURAVIN, N. M. DUBROVSKAYA, S. A. PLESNEVA

Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia

 


Summary
The role of the striatal adenylyl cyclase (AC) and cholinergic systems in the learning and expression of new forepaw movements (reaching with prolonged pushing on a fixed piston) was studied in male Wistar rats. Motor learning processes, prenatal hypoxia, and cholinergic drugs changed the properties of the AC system in the striatum. After learning, the striatal basal AC activity was decreased compared to untrained control rats. In addition, the AC activity was more decreased in animals with a good ability to learn compared to poor learners (up to 31 % and 51 %, correspondingly; p<0.01). Rats subjected to prenatal hypoxia (13-14th days of embryogenesis) had a lower ability to learn the new movements requiring tactile control and the striatal AC activity in these rats was 1.8 times higher (p<0.001) than controls. In vitro application of the cholinergic agonist carbachol (CARB) 10-5 M (corresponding to ~ 0.3 g), as well as the antagonist scopolomine (SCOP) 10-5 M (~ 0.3 g) decreased AC activity in the synaptosomal fraction of the striatum. In vivo injections of CARB (0.3-3 g/1l) or SCOP (0.3-3 g/1l) into the ventral striatum (nucleus accumbens) modified the newly learned sensorimotor skill. After CARB injections the rats performed slower movements with more prolonged pushing. After SCOP the rats could not retain the learned pushing movement. These in vivo and in vitro data suggest that the cholinergic mediator system of the striatum is involved in learning sensory-controlled forepaw movements as well as the regulation of new motor skills by modulating the AC signal transduction process in the striatum. The data confirmed that modification of the striatal AC system resulted in the modulation of reaching behavior and better expression of the learned reflex.


Key words
Striatum • Cholinergic systém • Adenylyl cyclase • Learning • Reaching movement • Rat


Reprint requests
Dr. Igor A. Zhuravin, PhD, DSc., Head of the Department of the Comparative Physiology and Pathology of the CNS,
Institute of Evolutionary Physiology and Biochemistry, RAS. M.Thorez av., 44, 194223, St.Petersburg, Russia.
Tel.: 7(812)5523166; Fax.: 7(812)5523012. e-mail: zhuravin@iephb.ru


PHYSIOLOGICAL RESEARCH
© 2002 by the Institute of Physiology, Czech Academy of Sciences

ISSN 0862 - 8408

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