The effect of the cerebrum acetylcholine and acetylcholinesterase in neonatal mice treated with different iodine doses before and after Morris water maze training

Objective: To detect the cerebrum acetylcholine (Ach) content and acetyleholinesterase (AchE) activeness of the Kunming 25-day neonatal mice treated with different high iodine doses before and after Morris water maze training. Methods: The weaning KM mice were randomly divided into five groups. The high iodine model mice were successfully duplicated by feeding for 100 days with distilled water containing different KIO3 concentrations, i.e. 50(I), 250 (II), 500 (III) , 1 500 (IV), and 3 000 (V) mg.L-1 respectively. The group took 50 mg·L-1 of proper iodine dose was of control group, and the groups of 250-3 000 mg.L-1 were of high iodine groups. The model mice were mated at a ratio of 1 male to 2 female. The 20-day neonatal mice were trained with the Morris water maze to build them the learning and memory function. The cerebrum acetylcholine content and acetylcholinesterase activity of the KM 25-day neonatal mice were detected. Twelve samples of each group of pre-Morris water maze training and ten samples of each group of after-Morris water maze training were detected. Results: 1 The escape latency of all groups but III group was significantly decreased with the increase of the experiment times of the mice (P < 0.05). The escape latency of mice in part of the experiment was obviously different among all groups, showing that the escape latency of mice in high iodine groups was longer than that in control group (P < 0.05). 2 Before Morris water maze training, the cerebrum Ach concentration in IV and V groups evidently decreased than that in control group (P < 0.05), after Morris water maze training, the Ach concentration in II and III groups obviously decreased than that in control group (P < 0.05). The Ach concentration in all groups but II group of the after-Morris water maze was more than that of pre-Morris water maze (P < 0.05). 3 The cerebrum AchE activities of the pre- and after-Morris water maze mice were detected that there was an evident difference among all groups, however the AchE activity in II-IV groups was not obviously different from the control group either of pre-Morris water maze or after-Morris water maze. Conclusions: High iodine can result in the hindrance of the learning ability and memory of the neonatal mice, which is relevant to the decrease of cerebrum Ach concentration. Intensifying the learning ability and memory function of the mice would enhance the cerebrum Ach content of the mice, which is irrelevant to the change of cerebrum Ache activity.