[Effect of three kinds of drinking water on learning and memory and hippocampal neurotransmitter of mice]

To explore the effect of three kinds of drinking water on learning and memory and hippocampal neurotransmitter of mice.

Water quality parameters, including total dissolved solid( TDS), total hardness, oxygen consumed( OC), sodium, potassium, calcium, magnesium and metasilicic acid, were measured for pure water, tap water and natural mineral water. A total of 60 ICR mice( half male and half female) were randomly divided into three groups and fed with pure water( control group), tap water and mineral water for 90 days. After learning-memory abilities were detected with Morris water maze and passive avoidance test, mice were killed and hippocampi were removed immediately to measure contents of acetylcholine( Ach), nitric oxide( NO), glutamic acid( Glu) and gamma-aminobutyric acid( GABA) and activities of acetylcholinesterase( ACh E), choline acetyltransferase( Ch AT) and total nitric oxide synthase( T-NOS).

Water quality parameters were higher in tap water and natural mineral water than in pure water. On the first day of place navigation test, the escape latency of tap water group [( 69. 15 ± 50. 87) s]was obviously shorter than that of pure water group [( 86. 07 ± 44. 03) s]( P < 0. 05), and mice in tap water group chose effect strategies( 51. 25%) more frequently compared to control mice( 30%)( P <0. 05). In the probe trial, the swimming time of the targeted quadrant was significantly longer in tap water group [( 28. 44 ± 10. 17) s] or mineral water group [( 28. 81 ±12. 43) s] than in pure water group [( 19. 84 ± 9. 59) s ]( P < 0. 05). In passive avoidance test, the training latency and testing latency were significantly longer in tap water group [( 60. 27 ± 57. 84) and( 209. 54 ± 121. 41) s] or mineral water group[( 58. 12 ± 42. 52) and( 271. 40 ± 90. 44) s]than in pure water group [( 10. 99 ± 9. 40)and( 72. 77 ± 67. 51) s ]( P < 0. 05), as the frequency of electric shock and the percentage of animals showing errors in tap water group [( 0. 90 ± 0. 88) times and 50%]or mineral water group [( 0. 10 ± 0. 32) times and 20%]were obviously less than those in pure water group [( 5. 00 ± 4. 62) times and 90% ]( P < 0. 05). Compared with pure water group [( 8. 53 ± 2. 12) μg / mg prot and( 0. 94 ± 0. 49) U / mg prot], a significant increase of Ach concentration and a significant decrease of ACh E activity were observed in tap water group [( 11. 18 ± 3. 46) μg / mg prot and( 0. 41 ± 0. 21) U / mg prot]or mineral water group [( 12. 91 ± 3. 91) μg / mg prot and( 0. 54 ± 0. 28) U / mg prot]( P < 0. 05).

Compared with pure water, long-term drinking tap water or mineral water is more beneficial to learning and memory of mice, and it may be associated with a higher content of hippocampal Ach.