A concise historical perspective of the area postrema structure and function / Uma perspectiva histórica concisa da estrutura e função da área postrema

ABSTRACT First described by Retzius at the end of the 19th century, the structure in the posterior medulla oblongata, then named area postrema, underwent an intense investigation into its function in the decades that followed. Findings, mainly in animal studies, have partially elucidated its role as an emetic center in the central nervous system. In the second half of the 20th century, this function was associated with reports of syndromes characterized by uncontrollable nausea and vomiting related to structural damage in the area postrema, mainly in the context of demyelinating diseases. At the beginning of the 21st century, the so-called area postrema syndrome has been consolidated as a diagnostic factor in diseases related to the spectrum of neuromyelitis optica, more than 100 years after its first description.

RESUMO Descrita pela primeira vez por Retzius no final do século XIX, a estrutura na medula oblonga posterior, então nomeada de área postrema, passou por intensa investigação quanto à sua função nas décadas seguintes. Achados sobretudo em estudos com animais elucidaram parcialmente sua função como centro emético no sistema nervoso central. Na segunda metade do século XX, tal função foi associada a relatos de síndromes caracterizadas por náuseas e vômitos incoercíveis relacionadas a lesões estruturais na área postrema, principalmente no contexto das doenças desmielinizantes. Já no início do século XXI, a então chamada síndrome da área postrema se consolida como fator diagnóstico nas doenças relacionadas ao espectro da neuromielite óptica, mais de 100 anos sua primeira descrição.

Neuromyelitis Optica Spectrum Disorder Presented with Upbeat Nystagmus and Intractable Vomiting / 대한평형의학회지

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory demyelinating autoimmune disease of central nervous system characterized by relapsing attacks that target the optic nerves and spinal cord, as well as aquaporin-4 (AQP4) enriched periventricular brain regions. The area postrema (AP), located in the dorsal medulla, is the chemosensitive vomiting center and has high AQP-4 expression. The AP syndrome with unexplained hiccups, nausea, and vomiting is one of the core clinical characteristics in the NMOSD and maybe the first presenting symptom. We experienced a 25-year-old woman presented with intractable vomiting, dizziness and oscillopsia. Upbeat nystagmus detected on the bedside examination led to comprehensive neurological workups including magnetic resonance imaging, and she was diagnosed as the AP syndrome. Ten months later, she experienced a recurrence as a longitudinally extensive transverse myelitis and the diagnosis was finally compatible with NMOSD without AQP4-IgG. NMOSD, especially the AP syndrome, should be considered in any dizzy patient with intractable vomiting, and detailed neuro-otologic and neuro-ophthalmologic examinations are warranted for the correct diagnosis.

Intractable Vomiting as an Initial Manifestation of Neuromyelitis Optica

No abstract available.

The Brainstem Area Postrema may Not be Involved in Lithium-induced Activation of the Hypothalamic-pituitary-adrenal Axis

The brainstem area postrema (AP) has been suggested to be one potential site of lithium's action. In order to determine whether the AP, as a central action site of lithium, is involved in the hypothalamic-pituitary-adrenal (HPA) activation by lithium, we examined lithium-induced expression of inducible cAMP early repressor (ICER) gene in the adrenal gland of rat with lesion of AP. The adrenocortical ICER expression has been suggested to be a marker for the HPA axis activation. Sprague-Dawley rats with lesion or sham lesion of AP received intraperitoneal injection of 0.15 M LiCl at a dose of 12 ml/kg. One hour after the injection, rats were transcardially perfused with fixative and the adrenal glands were processed for ICER mRNA in situ hybridization. ICER mRNA levels in the adrenal cortex of sham lesion rats were significantly increased by lithium, compared to NaCl controls, and this increase was not affected by AP lesion. Our results suggest that the area postrema may not be involved in lithium's action to activate the HPA axis.

Intracerebroventricular administration of adrenomedullin activates area postrema neurons in sino-aortic denervated rats / 基础医学与临床

Objective To examine the effects of intracerebroventricular administration of adrenomedullin (AM) on the expression of Fos and spontaneous electric activity of area postrema (AP) neurons in sino-aortic denervated rats. Methods To determine the expression of Fos and the spontaneous electrical activity of AP neurons in male Sprague-Dawley rats by immunohistochemistry. Results Following Intracerebroventricular administration of AM (1 nmol/kg, 3 nmol/kg), Fos-like immunoreactive (Fos-LI) neurons and the discharge rate of AP neurons markedly increased. Pretreatment with calcitonin gene-related peptide(CGRP) receptor antagonist CGRP8-37 (30 nmol/kg) significantly inhibited the effects of AM (3 nmol/kg). Conclusion AM may activate the neurons in AP via CGRP receptors.

Ultrastructure of the Area Postrema of the Bat / 대한해부학회지

This study was undertaken to investigate the ultrastructure of the neurons, neuroglial cells and capillaries in the area postrema[AP] of the Oriental discolured bat, Vespertilio superans. The AP of the bat was a single midline structure at the most caudal portion of the fourth ventricle. Most neurons in the AP were small cells, but their ultrastructure were similar to the typical neurons located elsewhere in the central nervous system. Astroglial cells and oligodendrocytes were also observed and showed their typical ultrastructure. Ultrastructural features of neurons, astroglial cells and oligodendrocytes were not changed during hibernating cycles. However, microglial cells were only found in the hibernating AP ; these cells were located in the parenchyma and near the blood vessels of the AP. Since the microglial cytoplasm was filled with phagocytotic inclusions, the nuclei of the these cells were eccentrically located. Phagocytotic cytoplasmic inclusions were shown to be composed of a dense irregular peripheral region and the pale round central region. A Large vacant space was often found in the electron lucent central region. Continuous and fenestrated capillaries surrounded by pericytes were found in the bat`s AP. Especially, Phagocytotic inclusions were found in the pericyte cytoplasm of the hibernating AP, and this result supports suggestion that pericytes might be phagocytotic cells. On the basis of the distributions of phagocytotic tells[pericytes and microglial cell], ultrastructure of these cells, morphology of their cytoplasmic inclusions, and the appearance of phagocytotic activity of the pericytes during the hibernating stage when microglial cells were observed, it can be concluded that pericytes may also participates in the formation of rrlicroglial cells. Tanycytes were also found in the bat AP.