Neuroscience
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Retracted Publication
GABAA receptors expression pattern in rat brain following low pressure distension of the stomach.
It is known that gastric mechanoreceptor stimuli are widely integrated into neuronal circuits that involve visceral nuclei of hindbrain as well as several central brain areas. GABAergic neurons are widely represented in hindbrain nuclei controlling gastric motor functions, but limited information is available specifically about GABA(A)-responding neurons in brain visceral areas. The present investigation was designed to determine the central sensory neuronal pathways and their GABA(A)-alpha1 and -alpha3 receptor presenting neurons that respond to gastric mechanoreceptor stimulation within the entire rat brain. ⋯ In contrast, during the tonic-rapid gastric distension the neuronal activation was found in hindbrain, midbrain and forebrain areas. Moreover different protocols of gastric stimulation activated diverse patterns of neurons presenting GABA(A)-alpha1 or -alpha3 receptors within responding brain nuclei, which may indicate a probable functional significance of differential expression of GABA(A)-responding neurons. The same protocol of gastric distension performed in vagotomized rats has confirmed the primary role of the vagus in the response of activation of gastric brain areas, whereas neuronal input of splanchnic origins was shown to play an important role in modulating the mechanogastric response of brain areas.
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Retracted Publication
The hippocampus in spontaneously hypertensive rats: a quantitative microanatomical study.
The influence of hypertension on the morphology of hippocampus was assessed in spontaneously hypertensive rats of two, four and six months and in age-matched normotensive Wistar-Kyoto rats. Values of systolic pressure were slightly increased in two-month-old spontaneously hypertensive rats in comparison with age-matched Wistar-Kyoto rats and augmented progressively with age in spontaneously hypertensive rats. No microanatomical changes were observed in the hippocampus of spontaneously hypertensive rats of two months in comparison with age-matched Wistar-Kyoto rats, whereas a decrease of white matter volume was observed in the CA(1) subfield and in the dentate gyrus of four-month-old spontaneously hypertensive rats. ⋯ The only change noticeable in the CA(3) subfield of six-month-old spontaneously hypertensive rats was a slight increase in the number of glial fibrillary acid protein-immunoreactive astrocytes. These findings indicate the occurrence of neuronal loss and of astrocyte changes in the hippocampus of spontaneously hypertensive rats of six months, being the CA(1) subfield the area most affected. The relevance of these neurodegenerative changes in hypertension and the possible occurrence of apoptosis and/or necrosis as expression of hypertensive brain damage is discussed.