Confirmation of the presence of serotonergic cells in the fetal cerebral cortex in cultures and in situ

Alfonso Boyzo-Montes de Oca, Laboratorio de Neuroquímica, Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados (CINVESTAV), Instituto Politécnico Nacional, Ciudad de México, México
Gabriel Manjarrez-Gutiérrez, Unidad de Investigación en Enfermedades Neurológicas, Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México; Laboratorio de Patología Molecular, Unidad de Investigación Biomolecular, Hospital de Cardiología, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México; México
Jorge Hernández-Rodríguez, Centro de Comunicación Prenatal, Querétaro, Querétaro. México

Background: Early appearance of serotonin in the fetal brain and its effects on brain morphogenesis support its neurotrophic role. Objective: To determine the presence of serotonergic cells and the expression of tryptophan-5-hydroxylase (TPH), 5-hydroxytryptamine (5-HT), serotonin transporter (SERT), 5-HT1A receptor and Pet-1 during the development of the cerebral cortex, both in situ and in tissue cultures. Material and methods: A descriptive, observational study was carried out in pregnant Wistar rats. The presence of the plug was regarded as the beginning of gestation. On days 13, 16 and 17, cesarean sections were performed to obtain the fetuses, and the brains were then immediately dissected to identify the presence of serotonergic cells, TPH, 5-HT, SERT, 5-HT1A and Pet-1 in tissue cultures and in situ by immunostaining detected on a confocal microscope. Results: Serotonergic cells and terminals were observed in the midbrain on day 17 of gestation, and in neopallium cocultures on days 13 and 16. TPH, 5-HT, SERT and Pet-1 immunopositive cells were also observed in the neopallium on day 12 of culture. Conclusions: The presence of serotonergic cells and other elements of the serotonergic system in the early cerebral cortex was confirmed, which may be transient and participate in cortical maturation processes during brain development.

Keywords: Cerebral cortex. Serotonergic neurons. Serotonin. Tryptophan-5-hydroxylase