Evaluation of Motor Cortex Neuronal Morphology in Developmental Hyperserotonemia Rat Model
Fetal serotonin levels are involved in the development of the serotonergic system in an autoregulatory manner as well as the organization and connectivity of non-serotonergic neurons. Insufficient serotonin levels during development result in improper neuronal maturation and decreased synaptogenesis. Conversely, excess developmental serotonin levels can alter the progression of serotonergic neurons, ultimately resulting in a chronic decrease of serotonin in the developed brain via a negative feedback mechanism. There is a known correlation between autistic patients and chronically decreased brain serotonin concentrations; this is potentially implicated in the impaired development of the autistic brain. Incomplete or delayed development of motor ability is a hallmark symptom and diagnostic consideration of ASD. The association of developmental hyperserotonemia and abnormal development of the motor cortex remains largely unstudied. This study proposes a method to further analyze the morphology and connectivity of cortical neurons located in the rat motor cortex. Ballistic transfection of the carboxylipophilic dye DiI and subsequent imaging using confocal microscopy allows visualization and quantification of neuronal morphology. This study employs an adapted procedure allowing staining of multiple tissue sections at once using a BioRad Helios chambered gene gun.