Uptake of exogenous protein by supraependymal cells of the feline area postrema

1979 ◽  
Vol 35 (4) ◽  
pp. 539-541 ◽  
Author(s):  
R. A. Leslie ◽  
D. G. Gwyn ◽  
J. A. Love
Author(s):  
Shams M. Ghoneim ◽  
Frank M. Faraci ◽  
Gary L. Baumbach

The area postrema is a circumventricular organ in the brain stem and is one of the regions in the brain that lacks a fully functional blood-brain barrier. Recently, we found that disruption of the microcirculation during acute hypertension is greater in area postrema than in the adjacent brain stem. In contrast, hyperosmolar disruption of the microcirculation is greater in brain stem. The objective of this study was to compare ultrastructural characteristics of the microcirculation in area postrema and adjacent brain stem.We studied 5 Sprague-Dawley rats. Horseradish peroxidase was injected intravenously and allowed to circulate for 1, 5 or 15 minutes. Following perfusion of the upper body with 2.25% glutaraldehyde in 0.1 M sodium cacodylate, the brain stem was removed, embedded in agar, and chopped into 50-70 μm sections with a TC-Sorvall tissue chopper. Sections of brain stem were incubated for 1 hour in a solution of 3,3' diaminobenzidine tetrahydrochloride (0.05%) in 0.05M Tris buffer with 1% H2O2.


BMC Neurology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chenyang Zhang ◽  
Kang Zhang ◽  
Bing Chen ◽  
Jiao Yin ◽  
Miaomiao Dong ◽  
...  

Abstract Background Neuromyelitis optica spectrum disorders (NMOSD), a group of autoimmune neurological diseases, involve the optic nerve, spinal cord, and brain. Meningitis is rarely reported as the primary clinical manifestation of both anti-aquaporin-4 (AQP4)/ anti-myelin oligodendrocyte glycoprotein (MOG) antibody-negative NMOSD (NMOSDneg). Case presentation A 30-year-old man initially presented with fever, headache, and neck stiffness. Lumbar puncture revealed mixed cell reaction and decreased glucose levels. As a result, tuberculous meningitis was suspected. After 1 month, the patient developed longitudinally extensive transverse myelitis and area postrema syndrome. This was followed by the presentation of meningitis-like symptoms once again in the third attack, but his condition eventually improved after corticosteroid treatment without relapse for 2 years. However, he was readmitted to our hospital owing to symptoms of diplopia, hiccup, and numbness in the right hand. Brain magnetic resonance imaging (MRI) revealed that the area postrema still contained lesions. Spinal MRI revealed several segmental enhancements at the C4–C5, T1, and T5 levels. Anti-AQP4 and anti-MOG antibodies were persistently absent in the serum and cerebrospinal fluid (CSF). The patient was finally diagnosed with NMOSDneg. Conclusions Meningitis could be a recurrent manifestation of NMOSDneg and requires more careful evaluation.


Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 658
Author(s):  
Erin L. Wood ◽  
David G. Christian ◽  
Mohammed Arafat ◽  
Laura K. McColl ◽  
Colin G. Prosser ◽  
...  

Adjustment of protein content in milk formulations modifies protein and energy levels, ensures amino acid intake and affects satiety. The shift from the natural whey:casein ratio of ~20:80 in animal milk is oftentimes done to reflect the 60:40 ratio of human milk. Studies show that 20:80 versus 60:40 whey:casein milks differently affect glucose metabolism and hormone release; these data parallel animal model findings. It is unknown whether the adjustment from the 20:80 to 60:40 ratio affects appetite and brain processes related to food intake. In this set of studies, we focused on the impact of the 20:80 vs. 60:40 whey:casein content in milk on food intake and feeding-related brain processes in the adult organism. By utilising laboratory mice, we found that the 20:80 whey:casein milk formulation was consumed less avidly and was less preferred than the 60:40 formulation in short-term choice and no-choice feeding paradigms. The relative PCR analyses in the hypothalamus and brain stem revealed that the 20:80 whey:casein milk intake upregulated genes involved in early termination of feeding and in an interplay between reward and satiety, such as melanocortin 3 receptor (MC3R), oxytocin (OXT), proopiomelanocortin (POMC) and glucagon-like peptide-1 receptor (GLP1R). The 20:80 versus 60:40 whey:casein formulation intake differently affected brain neuronal activation (assessed through c-Fos, an immediate-early gene product) in the nucleus of the solitary tract, area postrema, ventromedial hypothalamic nucleus and supraoptic nucleus. We conclude that the shift from the 20:80 to 60:40 whey:casein ratio in milk affects short-term feeding and relevant brain processes.


1990 ◽  
Vol 258 (1) ◽  
pp. R70-R76 ◽  
Author(s):  
S. Papas ◽  
P. Smith ◽  
A. V. Ferguson

Extracellular single-unit recordings from neurons in the area postrema (AP) and the nucleus tractus solitarius (NTS) in anesthetized male rats demonstrated that most cells in these regions have spontaneous activities of 5 Hz or less. Systemic angiotensin (ANG II) (50-500 ng) enhanced the activity of 55% of AP cells tested (n = 76), whereas 53% of tested NTS neurons (n = 62) were inhibited by ANG II. To determine whether these neurons were influenced specifically by circulating ANG II or by the accompanying increase in mean arterial blood pressure (BP), the effects of adrenergic agonists given intravenously on ANG II influenced neurons were also examined. Subsequently two cell types were characterized: cells responding to iv ANG II but not to the adrenergic agonist ("ANG II sensitive") and cells responding in a similar way to both agents ("BP sensitive"). Most ANG II-responsive neurons in the AP (53.5%) and the NTS (65%) were determined to be BP sensitive. These data demonstrate that ANG II influences the activity of AP neurons. In addition, there exists a second population of AP neurons apparently responsive to perturbations of the cardiovascular system. These studies further emphasize the potential roles of the AP in the regulation of body fluid balance.


2021 ◽  
Vol 14 (6) ◽  
pp. 558
Author(s):  
Verena Peek ◽  
Lois M. Harden ◽  
Jelena Damm ◽  
Ferial Aslani ◽  
Stephan Leisengang ◽  
...  

High mobility group box (HMGB)1 action contributes to late phases of sepsis, but the effects of increased endogenous plasma HMGB1 levels on brain cells during inflammation are unclear. Here, we aimed to further investigate the role of HMGB1 in the brain during septic-like lipopolysaccharide-induced inflammation in rats (LPS, 10 mg/kg, i.p.). HMGB-1 mRNA expression and release were measured in the periphery/brain by RT-PCR, immunohistochemistry and ELISA. In vitro experiments with disulfide-HMGB1 in primary neuro-glial cell cultures of the area postrema (AP), a circumventricular organ with a leaky blood–brain barrier and direct access to circulating mediators like HMGB1 and LPS, were performed to determine the direct influence of HMGB1 on this pivotal brain structure for immune-to-brain communication. Indeed, HMGB1 plasma levels stayed elevated after LPS injection. Immunohistochemistry of brains and AP cultures confirmed LPS-stimulated cytoplasmatic translocation of HMGB1 indicative of local HMGB1 release. Moreover, disulfide-HMGB1 stimulation induced nuclear factor (NF)-κB activation and a significant release of interleukin-6, but not tumor necrosis factor α, into AP culture supernatants. However, only a few AP cells directly responded to HMGB1 with increased intracellular calcium concentration. Interestingly, priming with LPS induced a seven-fold higher percentage of responsive cells to HMGB1. We conclude that, as a humoral and local mediator, HMGB1 enhances brain inflammatory responses, after LPS priming, linked to sustained sepsis symptoms.


1998 ◽  
Vol 274 (1) ◽  
pp. R97-R103 ◽  
Author(s):  
Yasuhiro Nishida ◽  
Isao Sugimoto ◽  
Hironobu Morita ◽  
Hiroshi Murakami ◽  
Hiroshi Hosomi ◽  
...  

Sodium ions absorbed from the intestine are postulated to act on the liver to reflexly suppress renal sympathetic nerve activity (RSNA), resulting in inhibition of sodium reabsorption in the kidney. To test the hypothesis that the renal sympathoinhibitory response to portal venous NaCl infusion involves an action of arginine vasopressin (AVP) at the area postrema, we examined the effects of portal venous infusion of hypertonic NaCl on RSNA before and after lesioning of the area postrema (APL) or after pretreatment with an AVP V1 receptor antagonist (AVPX). Rabbits were chronically instrumented with portal and femoral venous catheters, femoral arterial catheters, and renal nerve electrodes. Portal venous infusion of 9.0% NaCl (0.02, 0.05, 0.10, and 0.15 ml ⋅ kg−1 ⋅ min−1of 9.0% NaCl for 10 min) produced a dose-dependent suppression of RSNA (−12 ± 3, −34 ± 3, −62 ± 5, and 80 ± 2%, respectively) that was greater than that produced by femoral vein infusion of 9.0% NaCl (2 ± 3, −3 ± 2, −12 ± 4, and −33 ± 3%, respectively). The suppression of RSNA produced by portal vein infusion of 9.0% NaCl was partially reversed by pretreatment with AVPX (−9 ± 3, −20 ± 3, −41 ± 4, and −55 ± 4%, respectively) and by APL (−11 ± 2, −25 ± 2, −49 ± 3, and −59 ± 6%, respectively). There were no significant differences between the effects of AVPX and APL, and the effect of APL was not augmented by AVPX. These results indicate that the suppression of RSNA due to portal venous infusion of 9.0% NaCl involves an action of AVP via the area postrema.


Neurosurgery ◽  
2013 ◽  
Vol 72 (5) ◽  
pp. 855-860 ◽  
Author(s):  
Pierluigi Longatti ◽  
Luca Basaldella ◽  
Francesco Sammartino ◽  
Alessandro Boaro ◽  
Alessandro Fiorindi

Abstract BACKGROUND: Fluorescein enhancement to detect retinal disorder or differentiate cancer tissue in situ is a well-defined diagnostic procedure. It is a visible marker of where the blood-brain barrier is absent or disrupted. Little is reported in the contemporary literature on endoscopic fluorescein-enhanced visualization of the circumventricular organs, and the relevance of these structures as additional markers for safe ventricular endoscopic navigation remains an unexplored field. OBJECTIVE: To describe fluorescein sodium–enhanced visualization of circumventricular organs as additional anatomic landmarks during endoscopic ventricular surgery procedures. METHODS: We prospectively administered intravenously 500 mg fluorescein sodium in 12 consecutive endoscopic surgery patients. A flexible endoscope equipped with dual observation modes for both white light and fluorescence was used. During navigation from the lateral to the fourth ventricle, the endoscopic anatomic landmarks were first inspected under white light and then under the fluorescent mode. RESULTS: After a mean of 20 seconds in the fluorescent mode, the fluorescein enhanced visualization of the choroid plexus of the lateral ventricle, median eminence–tuber cinereum complex, organum vasculosum of the lamina terminalis, choroid plexus of the third and fourth ventricles, and area postrema. CONCLUSION: Fluorescein-enhanced visualization is a useful tool for helping neuroendoscopists recognize endoscopic anatomic landmarks. It could be adopted to guide orientation when the surgeon deems an endoscopic procedure unsafe or contraindicated because of unclear or subverted anatomic landmarks. Visualization of the circumventricular organs could add new insight into the functional anatomy of these structures, with possible implications for the site and safety of third ventriculostomy.


Peptides ◽  
2004 ◽  
Vol 25 (6) ◽  
pp. 985-989 ◽  
Author(s):  
James E Cox ◽  
Alan Randich

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