Open field behavior in nucleus basalis magnocellularis-lesioned rats treated with physostigmine and verapamil

The present study was done to investigate and compare the effect of acetylcholinesterase inhibitor, physostigmine (0.030, 0.045, 0.060 and 0.075 mg/kg sc) and Ca-antagonist, verapamil (1.0, 2.5, 5.0 and 10.0 mg/kg sc) on open field behavior in male Wistar rats with bilateral electrolytic lesions of nucleus basalis magnocellularis (NBM). NBM-lesions produced a significant increase and decrease of ambulation and number of inner squares entered, and defecation, respectively, with no influence on grooming in rats exposed to novel environment. Physostigmine and verapamil in all tested doses, given 30 min before the test did not affect the open field behavior in control animals. In contrast to that, physostigmine (0.045, 0.060 and 0.075 mg/kg) and verapamil (2.5 and 5.0 mg/kg) significantly reduced ambulation and number of inner squares entered in NBM-lesioned rats. Also, physostigmine in a dose of 0.060 mg/kg significantly decreased defecation and in doses of 0.060 and 0.075 mg/kg the grooming, as well. On the other hand, verapamil only in a dose of 2.5 mg/kg significantly increased defecation. It could be concluded that lesions of NBM in rats induced disturbances in the open field behavior, which might be successfully ameliorate by physostigmine and verapamil treatment.