Two Nootropic Drugs Taurine And Galantamine Lead To The Protection And Restoration Of The Role Of Synaptic Plasticity In Rat Hippocampal Dg Damage, Chronic Lead Exposure

Lead (Pb) induces a variety of learning and memory, cognitive dysfuntions and mental deseases. Long-term potentiation (LTP) and long-term depression (LTD) are two forms of synaptic plasticity, which are believed to underlie learning and memory. Previous studies have demonstrated that Pb impairs LTP of CA1 in vitro and LTP of dentate gyrus in vivo. The studies of this thesis were carried out to investigate whether the impairment of synaptic plasticity induced by chronic lead exposure can be reversed by two nootropic drug taurine and galantanine. The results are as follow:1. The experiments were carried out in four groups of rats (control, lead-exposed, control and lead-exposed with a taurinesupplement diet, respectively). The input-output (I/O) function, excitatory postsynaptic potential (EPSP) and population spike (PS) amplitude were measured in the dentate gyrus (DG) of adult rats (60-90 days) in response to stimulation applied to the lateral perforant path. The results show that: 1. chronic lead exposure impaired LTP/DP measured on both EPSP slope and PS amplitude in DG area of the hippocampus; 2. in control rats, taurine had no effect on LTP/DP; 3. the amplitudes of LTP/DP of lead-exposed group were significantly increased by applying taurine. These results suggest that dietary taurine supplement could protect rats from the lead-induced impairments of synaptic plasticity and might be a preventive medicine to cure the cognitive deficits induced by lead.2. Neonatal wistar rats were exposed to lead from parturition throughout life by the drinking of 0.3% PbAc solution. Galantamine were injected i.g at dose of lmg/100g /day two weeks before experiment. The result showed: 1. chronic lead exposure impaired LTP/DP measured on both EPSP slope and PS amplitude in DG area of the hippocampus; 2. in control rats, galantamine caused a small increase on the amplitude of LTP/DP; 3. the amplitudes of LTP/DP of lead-exposed group were significantly increased by applying galantamine. These results suggest that galantamine could reverse the lead-induced impairments of synaptic plasticity in rats and might be a effective medicine to cure the cognitive deficits induced by lead.