Synaptogenesis in the Dorsal Raphe Nucleus of the Medulla Oblongata in Rats in Conditions of Serotonin Deficiency

• Published in: Neuroscience and behavioral physiology 2013-10, Vol.43 (8), p.984-988
• Main Authors: Khozhai, L. I., Otellin, V. A.
• Format: Article
• Language: English
• Subjects: Animals; Behavioral Sciences; Biomedical and Life Sciences; Biomedicine; Brain; Fetuses; Neurobiology; Neurons; Neurosciences; Physiology; Prenatal development; Serotonin
• ISSN: 0097-0549; 1573-899X
• DOI: 10.1007/s11055-013-9840-y

Synaptogenesis in the dorsal raphe nucleus (DRN) of the medulla oblongata in Wistar rats was studied at the end of the prenatal (days 19 and 20) and during the early postnatal (days 5 and 20) periods (8–10 animals at each time point); the role of serotonin in forming synaptic contacts at this period of development was also assessed. In control animals (intact), the DRN-d, DRN-v, and DRN-l showed the onset of neuropil formation on day 19 of prenatal development; synaptic contacts appeared on processes at this time, first being detected on the surfaces of neuron bodies on day 20. The distribution density of synaptophysinpositive granules both on processes in the neuropil and on neuron bodies showed a sharp and significant increase by day 5 of postnatal development. Subsequent increases, to day 20, were minor. Serotonin deficiency during the second half of the period of intrauterine development, induced by administration of p-chlorophenylalanine to female animals on day 16 of pregnancy, led to significant delay in synaptogenesis in the DRN in the offspring during both the pre- and early postnatal periods. As postnatal age increased, increases in the distribution density of synaptic contacts were different in different parts of the DRN: contact density was similar to controls in the DRN-d, while it remained low in the DRN-v and DRN-l. These results provide evidence for the involvement of serotonin in synaptogenesis in the DRN.