PMID- 10091859
OWN - NLM
STAT- MEDLINE
DCOM- 19990519
LR  - 20131121
IS  - 0161-813X (Print)
IS  - 0161-813X (Linking)
VI  - 20
IP  - 1
DP  - 1999 Feb
TI  - The influence of developmental period of lead exposure on long-term potentiation 
      in the adult rat dentate gyrus in vivo.
PG  - 57-69
AB  - Previous work has demonstrated an increase in the threshold for induction of 
      long-term potentiation (LTP) in the dentate gyrus of animals chronically exposed 
      to lead (Pb) from birth (Gilbert et al., 1996). The present study sought to 
      extend these findings by evaluating the developmental periods critical for 
      Pb-induced impairment of LTP. Rats were exposed to Pb through maternal milk 
      and/or the drinking water over different developmental intervals: 1) beginning 
      just prior to birth and continuing throughout life (PL); 2) beginning just prior 
      to birth and terminating at weaning (PW); or 3) continuously from the early 
      post-weaning period throughout life (WL). Pregnant dams received 0.2% Pb-acetate 
      in the drinking water on gestational day (GD)16, with male offspring switched to 
      the same solution (PL group) or tap water (PW group) at weaning on postnatal day 
      (PND)21. Postweaning exposure began on PND30 and continued throughout life. As 
      adults (PND130-210), field potentials evoked by perforant path stimulation were 
      recorded in the dentate gyrus under urethane anesthesia, and an ascending series 
      of stimulus trains was administered to induce LTP and to determine its threshold. 
      The magnitude of population spike (PS) LTP was reduced relative to controls in 
      animals exposed throughout life (PL) and in animals exposed after weaning (WL). 
      No impairment in PS LTP was evident in animals removed from Pb at weaning and 
      tested as adults (PW). Similarly, thresholds for induction of PS LTP were 
      elevated relative to controls in the PL and WL groups, but were not affected by 
      Pb exposure limited to the lactational period (PW). Reductions in the magnitude 
      of LTP of the EPSP slope were evident in posttrain I/O functions in all 
      Pb-exposed groups, including the PW group. An elevated LTP threshold was evident 
      in the EPSP slope measure in the continuously exposed group (PL) only. Thus Pb 
      exposure restricted to the lactational period appeared less disruptive to adult 
      LTP in the dentate gyrus than continuous exposure beginning around birth or 
      weaning. However, EPSP slope LTP was impaired in animals exposed to Pb for as 
      little as 30 days in the early postnatal period. An attenuated ability to support 
      neuroplastic change in synaptic function may contribute to cognitive deficits 
      associated with Pb-induced toxicity.
FAU - Gilbert, M E
AU  - Gilbert ME
AD  - National Research Council and Neurotoxicology Division, U.S. Environmental 
      Protection Agency, Research Triangle Park, NC 27711, USA. 
      gilbert.mary@epamail.epa.gov
FAU - Mack, C M
AU  - Mack CM
FAU - Lasley, S M
AU  - Lasley SM
LA  - eng
GR  - ES-06253/ES/NIEHS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - Netherlands
TA  - Neurotoxicology
JT  - Neurotoxicology
JID - 7905589
RN  - 2P299V784P (Lead)
SB  - IM
MH  - Aging/*physiology
MH  - Animals
MH  - Animals, Newborn/physiology
MH  - Animals, Suckling/physiology
MH  - Brain/metabolism
MH  - Dentate Gyrus/drug effects/growth & development/*physiology
MH  - Electric Stimulation
MH  - Excitatory Postsynaptic Potentials/physiology
MH  - Female
MH  - Lead/blood/pharmacokinetics/*toxicity
MH  - Long-Term Potentiation/*drug effects
MH  - Male
MH  - Neurons, Afferent/drug effects
MH  - Pregnancy
MH  - Rats
MH  - Rats, Long-Evans
EDAT- 1999/03/26 00:00
MHDA- 1999/03/26 00:01
CRDT- 1999/03/26 00:00
PHST- 1999/03/26 00:00 [pubmed]
PHST- 1999/03/26 00:01 [medline]
PHST- 1999/03/26 00:00 [entrez]
PST - ppublish
SO  - Neurotoxicology. 1999 Feb;20(1):57-69.