Establishment of the GABAergic Neural Network in the Ventrolateral Part of the Solitary Tract Nucleus in Normal Conditions and in Prenatal Serotonin Deficiency in Rats

Abstract

The dynamics of the formation of the inhibitory neural GABAergic network in the ventral and lateral subnuclei of the solitary tract nucleus (STN) in the early postnatal period were studied in Wistar rats in normal conditions and in prenatal serotonin deficiency (n = 27). GABAergic neurons were detected immunocytochemically using rabbit polyclonal antibodies to GAD-67. The STN subnuclei studied were found to display high levels of GABA expression during the first week of postnatal development, as evidenced by the significant number of GAD-67-immunopositive neurons, of which the number in the ventral subnucleus was almost 1.3 times greater than that in the lateral subnucleus. GABA expression decreased during the second and third weeks, with a simultaneous increase in the density of the network of terminals and GABAcontaining synaptic structures in the neuropil of both subnuclei. Prenatal serotonin deficiency was found to produce sharp decreases in GABA expression in the ventral and lateral subnuclei of the STN during the early postnatal period of development. By the end of the third week, a loose network of GABAergic terminals persisted in the neuropil and the density of synaptic structures increased.