Lead induced alterations in nitrite and nitrate levels in different regions of the rat brain.
Nitric oxide (NO) is a free radical synthesized by nitric oxide synthase (NOS) during the conversion of L-arginine to citrulline. Lead (Pb) affects neuronal functioning in the rat brain. Nitric oxide, a neuronal messenger has a short half life and converts immediately into nitrite and nitrate. The present study is designed to determine lead-induced alterations in NO production by measuring nitrite and nitrate in the cerebellum, the hippocampus, the frontal cortex and the brain stem of the rat brain. Male Sprague-Dawley rats were treated with lead acetate (5 and 15 mg/kg body wt.) by intraperitoneal injection. The control and experimental rats were sacrificed at the end of 7 and 14 days after treatment and different regions of the brain were isolated. Nitrite and nitrate (NOx) levels were estimated by the chemiluminescent method using the NOA 280 (Sievers). The data suggested dose-dependent and region-specific responses to lead. Both treatments of lead reduced NOx levels in the cerebellum and the hippocampus. However, the frontal cortex and the brain stem responded differently to Pb exposure. NOx levels in the frontal cortex were significantly increased in rats treated with low and high doses of Pb for 7 days but not in rats treated for 14 days, whereas in the brain stem, NOx levels were increased in a dose- and time-dependent manner. Although, the response was time-dependent, the variation between 7- and 14-day treatment was not clearly delineated. These results provide additional evidence that Pb exposure alters NO-production in rat brain leading to neuronal dysfunction.
Chen
S M
SM
Department of Biology, Alcorn State University, 1000 ASU Drive, P.O. Box 870, Alcorn State, MS 39096, USA.
Swilley
S
S
Bell
R
R
Rajanna
S
S
Reddy
S L
SL
Rajanna
B
B
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D001933:Brain Stem / Q000187:drug effects / Q000378:metabolism; D002531:Cerebellum / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005625:Frontal Lobe / Q000187:drug effects / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009566:Nitrates / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism*; D009942:Organometallic Compounds / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley
D009566:Nitrates; D009573:Nitrites; D009942:Organometallic Compounds; D009569:Nitric Oxide; C008261:lead acetate