The Effects of Injection of Oxybutynin and Steroid Hormones into Hippocampus on Learning and Motion Balance in Rats

Background and Aim : It has been found that various neurotransmitters, including histamine H1 and acetylcholine, play a role in learning and increasing or decreasing motion balance. Since neurotransmitters with a medium neuron and in the steroid environment, have a different physiological function. Thus, the purpose of this study is to investigate the effects of injection of oxybutynin -muscarinic antagonist- and steroid hormones into hippocampus and their interaction on learning and motion activity in the hippocampus.Methods : In this experimental study, Twenty five adult male Wistar rats weighing 250-300g were randomly divided into the five following groups: Control, the groups received oxybutynin (3μl), oxybutynin plus Estradiol (2μl+1μl), oxybutynin plus progesterone(2μl+1μl), and oxybutynin plus Estradiol and Progesterone. Before surgery, the rats motion balance was examined with the rotarod set. Rats in the control groups did not received any drug. Animals in the drug groups were anesthetized by intraperitoneal injection of ketamine hydrochloride plus xylazine. They were placed in the stereotaxic apparatus and two cannulas implanted in 0.2mm above hippocampus. After a week of recovery, the drugs were injected through the cannulas in final volume of (3μl). At the end of the injection, to check the learning and memory criteria, motion balance were assessed by rotarod test (1, 3 and 24 h after the injection). The data were analyzed using one-way (ANOVA) followed by tukey s post hoc test.Results : The collected information from groups suggests that intra-hippocampus administration injection of oxybutynin significantly (p<0.01) reduced motion balance. Similarly, after 3h of the injection of oxybutynin plus estrogen, the result of rotarod test significantly (p<0.01) reduced similar to oxybutynin plus P4 and oxybutynin plus E2+P4 drug groups. On the contrary, 24h after the injection oxybutynin plus E2, the result of rotarod test in this group significantly improved motion balance than the other drug groups. The comparison of the rotarod test of each group -except the group mentioned- suggested that the motor balanced index in the control group has significantly reduced in (1, 3 and 24h ) after injection .The rotarod test of drug groups with respect to the pre-injection drug, showed a significant decrease at the level (p = 0.000). However, 24h after the injection, in the oxybutynin plus estrogen medication group, a significant increase was observed relative to the Rota rod test before injectionConclusion : it obviously seems that oxybutynin decrease the balance and motion activity. There is an interaction between oxybutynin and steroid hormones in the balance activity at the hippocampus.

کلیدواژه ها:

Oxybutynin ، Steroid Hormones ، Rat ، Learning ، Balance ، Motion activity