Summary. The aim of this study was to evaluate the distribution pattern of the different subtypes of the interstitial cells of Cajal (ICC), to understand their roles in gastrointestinal motility and interaction with the enteric nervous system depending on their location. Based on morphological analyses using the immunohistochemistry of whole mount preparations of mouse intestine, we investigated the normal local density and morphological features of ICC and statistically compared the number of the cells between the mesenteric and anti-mesenteric sides, and between the proximal and distal sites. Density gradients were shown in ICC associated with the deep muscular plexus, the myenteric plexus in the large intestine, and the longitudinal muscle. However, such changes in cell density were not always proportional to other subtypes, even in the same part of the intestine. As the pacemaker cells for intestinal motility, dense and seamless network connections were shown in ICC associated with the myenteric plexus in the small intestine and ICC associated with the submuscular plexus in the large intestine without any gradient of cell density, in contrast with the difference of morphological network patterns between proximal and distal sites. Thus, we conclude that the distribution patterns of ICC differ in cell density, morphological features, and network patterns, depending on the individual subtype and site of the intestine. Therefore, careful studies on the quantification and distribution of ICC under normal conditions should be important in diagnosing clinical disorders related to abnormal distribution of ICC.
Summary. Aquaporin-2 (AQP2) is a water channel protein that is trafficked between intracellular vesicles and the plasma membrane of kidney collecting duct cells upon vasopressin stimulation. Vasopressin changes the phosphorylation states of the AQP2 C-terminal serines (Sers), Ser256, Ser261, Ser264, and Ser269, in rats and mice, which is thought to play a role in controlling trafficking. Here, we focused on Ser269. We developed a specific antibody to Ser269-phosphorylated AQP2. Using immunofluorescence microscopy, we examined its localization in the rat kidney following injection of vasopressin and a vasopressin type 2 receptor-specific antagonist (OPC-31260). Ser269-phosphorylated AQP2 was almost undetectable in the water-loaded rat kidney, but was detected intracellularly soon after vasopressin injection, and then highly accumulated on the apical membrane of connecting tubule and collecting duct principal cells. In addition to the apical membrane, Ser269- phosphorylated AQP2 was also detected on the basolateral membrane of connecting tubule cells and inner medullary collecting duct principal cells. OPC-31260 injection following vasopressin stimulation caused internalization of AQP2, a pool of which was phosphorylated at Ser269. These results suggest that 1) AQP2 is phosphorylated at Ser269 intracellularly upon vasopressin stimulation and is rapidly trafficked to the plasma membrane, and 2) AQP2 can be internalized from the plasma membrane even if it remains phosphorylated at Ser269.
Summary. Neonatal hypoxic/ischemic (H/I) brain injury causes neurological impairment, including cognitive and motor dysfunction as well as seizures. Patterns of H/I injury-induced neuron death using rodent models are considered to be similar to the cases in human H/I encephalopathy. The participation of autophagy in neuron death has been a common feature in neonatal rodent models of H/I brain injury and human H/I encephalopathy when examined by immunochemical approaches for MAP1-LC3. This tendency has also been confirmed in neuronal tissue-specific Atg7 conditional knockout mice. However, while the current rat H/I model that is used for analyzing autophagy results in global damage to the ipsilateral hemisphere, it does not entirely reflect the neuropathological changes that appear in the neonatal mouse H/I model, in which the hippocampus is selectively damaged. The present study established a neonatal rat model of H/I injury with a milder ischemic insult, in which autophagy was involved in the hippocampal CA1 region after H/I injury when examined by electron microscopy, and by immunohistochemical and biochemical analyses of LC3.
In Xenopus laevis Daudin the anlage of the carotid labyrinth, a baro-and chemoreceptor, appears in early premetamorphosis (NF stage 53) as a swelling of the third aortic arch at the point where the common carotid artery gives off the external carotid artery.A conspicuous accumulation of melanocytes preceeds the formation of the labyrinth maze which starts to grow at the end of metamorphic climax (NF stage 64) and continues so through juvenile age.In adult animals the carotid labyrinth displays a spherical to ovoid shape, has an average length of 1.4 mm, a width of about 0.8 mm and a height of about 0.4 mm.The maze vessels form by sprouting angiogenesis from the common carotid artery and the internal carotid artery.Scanning electron microscopy of vascular corrosion casts reveals that size, overall shape, surface morphology and vascular patterns of the carotid labyrinth vary greatly between individuals, whereby intussusceptive microvascular growth (= nonsprouting angiogenesis) and its facets model and contribute to the maturation of the labyrinth's final vascular patterns.
The microvascularization of the pancreas of larval and adult South African Clawed Toads Xenopus laevis, was studied by scanning electron microscopy of vascular corrosion casts and light microscopy of paraplast embedded Goldner-stained serial tissue sections. We showed that branches of left and right gastric artery, hepatic artery and anterior intestinal artery, namely anterior pancreatic, anterior middle pancreatic, posterior middle pancreatic and caudal pancreatic arteries supply and pancreatic veins drain the adult pancreas into hepatic portal vein, anterior and middle gastric vein, gastroduodenal vein, and anterior duodenal vein. In premetamorphosis the pancreas showed a dense but immature vascular bed with signs of ongoing sprouting and non-sprouting angiogenesis (=intussusceptive microvascular growth; IMG). During metamorphic climax the pancreas shrinked dramatically paralleled by vascular regression.The larval pancreas had an underdeveloped ductal system which in the course of pancreas remodeling during metamorphic climax developed into a complex ductal system. In adult Xenopus laevis the pancreas showed intralobular islets of Langerhans only and an insuloacinar portal vessel system as described sofar in reptiles, birds and mammals. Islets in Xenopus located superficially and within deeper regions and emitted both insulo-acinar portal vessels and insulo-venous efferent vessels. Intrainsular microvascular patterns found suggest that in Xenopus islets blood flows first to β-cells and subsequently to the other endocrine cells present in the endocrine pancreas. Key words: Xenopus, pancreas, microvascularization, vascular casts, histomorphology
