The reversal effect of galantamine on enhanced locomotor activity due to microinjection of intrahippocampal colchicine in Wistar rats

Background and Objective: Deleterious effect of neurotoxins on the brains of animals is an attractive research topic. In this research, the effect of microinjection of colchicine into the hippocampal CA1 was shown by examining the novelty seeking behavior. Also, the effect of pre-injection of galantamine, an effective agent in the treatment and prevention of Alzheimer's disease, for reversal of colchicine’s side effect in that region was also examined.

Materials and Methods: Ninety six male Wistar rats were bilaterally cannulated at the hippocampal area (AP: -3.8 L: 1.8 ± 2.2 V: 3). They experienced a three-phase novelty seeking task in the unbiased conditioning apparatus after one week: in day 1, the animals moved freely (10 min) in the box to familiarize with the device over the next consecutive three days, they were confined in one part of the apparatus (40 min, twice daily) finally (Day 5), the animals were injected colchicine (25 µg/rat hippocampus, n = 8) prior to testing (lasted 10 min/similarly to the familiarization situation). The galantamine groups received the drug (1-25 µg/rat hippocampus n = 8) solely or prior to the colchicine. The negative control only received saline (1 µL/rat hippocampus).

Results: As the data show, the injection of colchicine significantly caused an increase in the locomotor activity of the treated animals. The lonely galantamine groups though showed no significant difference versus the control group, but in pre-galantamine groups, the enhanced activity was reversed.

Conclusion: The side effects of colchicine on the brain of the laboratory animals have been shown the most important of them is the destruction of granular neurons of the hippocampal formation. The effect of this material on the cortical pyramidal neurons is still unknown. The present study shows the increased locomotor activity of the animals due to the injection of colchicine into the hippocampus. This effect was reversed by pre-injection of galantamine and it is probable that the effect was modulated by the neuronal mediators.