Effect Of Acute Lead Exposure On PKC-γ, NOS, NO Of Rat Hippocampus

Lead has high affinity to nerve, and it can be accumulated in nerve tissue, which causes the long-period damage to nerve system, major to the memory and learning. The damage of low level lead exposure to the nervous to the nervous system of children in the environment, particularly to the impairment of learning and memory and mentality functions in children, is an important public health concern. Because of incompletely developed blood brain barrier, children who are exposure to lead as low as 100μg/L (blood lead level) show signifinant deficits of learning and memory and significant behavioral abnormal. So it is urgent to probe into lead nerve poisoning.As is known that lead can interfere the formation and maintain of LTP, the activity of PKC in hippocamp and the distribution of isoenzymes PKC-γby abnormally enhancing or inhibiting the activity of PKC.As cell signal molecule of the nervous system, Nitric Oxide can impact learing and memory function in hippocampus. Only NO synthase (NOS) can catalyse endogenesis NO, and determine its biology effect. NOS is one of target molecules in lead poisoning. The effects of chronic lead exposure on NOS and NO are observed in order to explore the effect of lead on them.The paper investigates the biochemistry mechanism of the effects of lead exposure on learning and memery from the view of cell signal transduction. Acute lead exposure result in PKC-γactivity abnomal; disturb NOS activity and NOcontent; impact learning and memory function. New point of view is advanced for the mechanism of lead poison. Methods1. Acute exposure to lead:For acute lead exposure in vitro , 350μm hippocampal slices were prepared. After 2 h culture, 20μmol·L^-1 lead acetate was added into the media , the slices were collected at different time .The control group in acute experiments used water instead of lead acetate.2. Prepare the samples:Took out the samples, added the buffer (NaCl 0.1mol/1, TrisCl 0.01mol/l, PH 7.6, EDTA 0.001mol/l, PH 8.0, PMSF 100μg/ml), then shattered by ultrasound, centrifuged at 27000G for 1hour at 4°C, moved the fluid phase into a new tube. Measured the content of protein by Lowery methord. Stored at -70°C.3. The expression of PKC-γwere determined by western blots. The activities of NOS and the content of NO were determined by their reagent.Results1 .Effect of lead on the activity of PKC-γIn acute experiment the activity of PKC-γof control group had no obvious changes, while decreased remarkably at 30 and 60 min. in acute lead exposure group , and returned to normal level at 120min .2 .Effect on the activities of NOS and the content of NOIn acute experiment the activities of NOS and the content of NO of control group had no obvious changes, while decreased remarkably at 30 and 60 min. in acute lead exposure group , and returned to normal level at 120min .Conclusions1. In acute experiment the activity of PKC-γof control group had no obvious changes, while decreased remarkably at 30 and 60 min. in acute lead exposure group , and returned to normal level at 120min .2.In acute experiment the activities of NOS and the content of NO of control group had no obvious changes, while decreased remarkably at 30 and 60 min. in acute lead exposure group , and returned to normal level at 120min .