RESUMO
Oxytocin (OXT) is a peptide hormone and a neuropeptide that regulates various peripheral physiological processes and modulates behavioral responses in the central nervous system. While the humoral release occurs from the axons arriving at the median eminence, the neuropeptide is also released from oxytocinergic cell axons in various brain structures that contain its receptor, and from their dendrites in hypothalamic nuclei and potentially into the cerebrospinal fluid (CSF). Understanding oxytocin's complex functions requires the knowledge on patterns of oxytocinergic projections in relationship to its receptor (OXTR). This study provides the first comprehensive examination of the oxytocinergic system in the prairie vole (Microtus ochrogaster), an animal exhibiting social behaviors that mirror human social behaviors linked to oxytocinergic functioning. Using light and electron microscopy, we characterized the neuroanatomy of the oxytocinergic system in this species. OXT+ cell bodies were found primarily in the hypothalamus, and axons were densest in subcortical regions. Examination of the OXT+ fibers and their relationship to oxytocin receptor transcripts (Oxtr) revealed that except for some subcortical structures, the presence of axons was not correlated with the amount of Oxtr across the brain. Of particular interest, the cerebral cortex that had high expression of Oxtr transcripts contained little to no fibers. Electron microscopy is used to quantify dense cored vesicles (DCV) in OXT+ axons and to identify potential axonal release sites. The ependymal cells that line the ventricles were frequently permissive of DCV-containing OXT+ dendrites reaching the third ventricle. Our results highlight a mechanism in which oxytocin is released directly into the ventricles and circulates throughout the ventricular system, may serve as the primary source for oxytocin that binds to OXTR in the cerebral cortex.
RESUMO
Os autores estudaram retrospectivamente 12 casos de enterocolite necrotizante (ECN) ocorridos em RNs no bercario do Hospital do Servidor Publico Estadual de Sao Paulo (HSPE), no periodo de l/l/77 a 3l/3/79,com o objetivo de analisar os fatores determinantes e as condutas para prevencao e controle desta patologia. Os dados referentes a estes RNs foram comparados aos da literatura, tendo sido feita uma analise estatistica referente a mortalidade do grupo, concluindo-se estar diretamente associada a anoxia perinatal, tempo de rotura de membranas, formula hiperosmolar para alimentacao, acidose metabolica e epoca do diagnostico no Servico. Nao houve relacao com o tipo de parto, idade gestacional, sexo, peso, tratamento cirurgico, aleitamento natural, numero de plaquetas e persistencia de canal arterial. Verificou-se ainda que nos primeiros seis casos da serie a mortalidade foi maior que nos seis ultimos, fato este relacionado com a precocidade do diagnostico e adequacao terapeutica
