Neurochemistry and Neuropharmacology
Author: Fernando Macías Martín | email: fmaciasmartin@fmed.uba.ar
Fernando Macías Martín 1°, Alicia Brusco 1°, Laura Caltana 1°
1° Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencias Prof. E. De Robertis. Buenos Aires. Argentina.
The Endocannabinoid system is present in the brain from early stages of embryonic development and it regulates key processes of brain development. Human studies have shown alterations in attention and memory process, hyperactivity and childhood depression in those whose mothers consumed cannabinoids during pregnancy. The aim of this work was to study structural changes in the adolescent brain of CB1R+/+ and CB1R-/- mice prenatally exposed to the synthetic non selective cannabinoid agonist WIN 55212-2 (WIN). Pregnant CB1R+/+ and CB1R-/- female mice were injected with WIN from GD5-GD20. After birth, lactation was performed from a substitute non-WIN exposed mother. At postnatal day 35 male pups were fixed and immunofluorescence staining was performed in coronal slices of the brain to analyze the expression of NeuN, MAP2, GFAP and NF200. CA1 hippocampal area showed a reduction in the number of neurons and astrocytes in CB1+/+ mice prenatally exposed to WIN, a reduction of the number of neurons and an increase in the astrocytic reaction in CB1-/- prenatally exposed mice. There were no changes in the dendritic arborization between CB1+/+ and CB1-/- mice, independently of WIN exposure. Motor cortex showed a non-significant decrease in the axonal area in the CB1+/+ and CB1-/- at M1 and M2 anterior cortex. CA1 hippocampal area is sensitive to prenatal WIN exposure and its alteration depends on the presence of CB1R. These changes could explain cognitive deficits observed in humans.