Guadalupe García Arenas, Ph.D.

Dr. Guadalupe Garcia Arenas, a PhD in biomedical sciences, is an associate investigator in the National Center of Environmental Health of Mexico’s National Institute of Public Health. She was awarded the Irving J. Selikoff Scholarship in 1997 to conduct research on the nitric oxide synthase inhibiting activities of lead acetate. She worked with Luz Claudio, Ph.D. while at Mount Sinai. Dr. Garcia Arenas’ research interests include toxicology, heavy metals and tobacco.

Institutional Affiliation

Centro Nacional de Salud Ambiental
Instituto Nacional de Salud Pública

Mailing Address

Instituto Nacional de Salud Pública
Col. Santa María Ahuacatitlán
Av. Universidad No. 655
Cuernavaca, Morelos
62508
MEXICO

E-mail Address

ggarenas1@yahoo.com

Irving J. Selikoff Scholarship Project

Lead Acetate Exposure Inhibits Nitric Oxide Synthase Activity in Capillary and Synaptosomal Fractions of Mouse Brain

The toxicity of lead (Pb) is of concern to public health due to its persistence in the environment. The brain is one of the major target organs where severe neurological alterations may be triggered after exposure. The primary effects of lead on brain functions are thought to be damage to the nervous system microvasculature. However, the mechanism of this toxicity is poorly understood. Nitric oxide synthase (NOS) may be a target for lead and changes in its function can result in a cascade of pathophysiological effects that may be observed in isolated capillaries and synaptosomes. We have determined the concentration of lead in blood, capillaries and synaptosomes in brain from mice receiving 0, 250, 500 and 1000 ppm of lead for 14 days through the drinking water. NOS activity was determined in the capillaries and synaptosomes by following the conversion of 3H-L-arginine to 3H-L-citrulline. The results show that blood lead levels were dose-dependent. Brain capillaries showed a preferential accumulation of lead as compared to synaptosomes. With all Pb treatments, synaptosomal and capillary constitutive NOS was inhibited (about 50% of control), while the form of NOS in capillaries was enhanced. These data suggest that inhibition of cNOS activity and increase in iNOS may contribute to the Pb effects on the CNS.

Partial Bibliography

G. Garcia-Arenas, F.J.Flores-Murrieta, C. Rios (1997). Anticonvulsive Effect of Dapsone: Interaction with Phenytoin in the Kainic Acid Model of Seizures. Proc. West. Pharmacol. Soc. 40: 95-96.-20

G. Garcia-Arenas, L. Claudio, F. Perez Severiano and C. Rios (1999). Lead Acetate Exposure Inhibits Nitric Oxide Synthase Activity in Capillary and Synaptosomal Fractions of Mouse Brain. Toxicological Sciences. 50, 244-248.