We have discovered a non-AT 1 , non-AT 2 angiotensin binding site in rodent and human brain membranes, which, based on its pharmacological/biochemical properties and tissue distribution, is different from angiotensin receptors and key proteases processing angiotensins. In this study, the novel angiotensin binding site was localized to a specific brain cell type by using radioligand receptor binding assays. Our results indicate that the novel binding site is expressed in mouse primary cortical neuronal membranes but not in primary cortical astroglial and bEnd.3 brain capillary endothelial cell membranes. Whole-cell binding assays in neurons showed that the binding site faces the outer side of the plasma membrane. Consistent with our previous observations, the novel binding site was unmasked by the sulfhydryl reagent p-chloromercuribenzoate. This effect had a bell-shaped curve and was reversed by reduced glutathione, indicating that the function of the binding site might be regulated by the redox state of the environment. Density of the novel binding site measured by saturation binding assays was significantly increased in neuronal membranes of cells challenged in four in vitro models of cell death (oxygen-glucose deprivation, sodium azide-induced hypoxia, N-methyl-D-aspartate neurotoxicity, and hydrogen peroxide neurotoxicity). In addition, our in vivo data from developing mouse brains showed that the density of the novel angiotensin binding site changes similarly to the pattern of neuronal death in maturating brain. This is the first time that evidence is provided on the association of the novel angiotensin binding site with neuronal death, and future studies directed toward understanding of the functions of this protein are warranted.

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The novel, non‐AT1, non‐AT2 angiotensin binding site is a yet unknown protein found in rodent and human brain membranes with pharmacological specificity and tissue distribution different from the type 1 and 2 angiotensin receptors and key enzymes involved in proteolytic processing of angiotensins. Here we report a summary of our recent studies indicating a correlation between the density of the novel binding site in primary neurons and neuronal cell death. 125I‐Sar1, Ile8 angiotensin II binding studies were carried out according to previously established procedures in mouse primary cortical neuronal membranes. Unmasking of the novel angiotensin binding site was carried out by 10 μM p‐chloromercuribenzoic acid (PCMB) in the presence of 10 μM PD123319 and 1 μM ZD7155 (AT1 & AT2 receptor antagonists). 12 in‐vitro‐day‐old primary neurons were challenged in three in vitro models of apoptosis (oxygen‐glucose deprivation for 3 hr, exposure to sodium azide (3 mM) or NMDA (0.5 mM) for 30 min in glucose free EBSS) followed by 24 hr recovery in normal medium. Density of the novel angiotensin binding site in neuronal membranes was estimated by saturation binding assays. The results indicated that the number of novel angiotensin binding sites was significantly elevated in neuronal membranes from all treatment groups, where the viability of neurons was significantly decreased. Supported by TTUHSC SOP start‐up funds to VTK.

Solid pseudopapillary tumor of pancreas is a rare tumor almost exclusively affecting the young female and accounts for <1% of all pancreatic tumors. Most hypothesis suggests that the tumor arises from embryonic pleuripotent stem cells. Although mostly benign in nature, the tumor may show malignant potentials and the patient may present with hepatic, omental or other meatstasis. High index of suspicion is the key for early dianosis. Good quality imaging (USG and CT scan) & FNAC are necessary for proper evaluation of the lesion. Peroperative frozen section biopsy may be necessary to ascertain its malignant potential. Radical resection is the best modality of treatment for achieving curative results and a better long-term survival. We are reporting our experience of treating a case of solid pseudopapillary tumor of pancreas in BIRDEM Hospital. Birdem Med J 2013; 3(1): 54-58 DOI: http://dx.doi.org/10.3329/birdem.v3i1.17129