Localization of endothelin-A and -B receptors during the postnatal development of rat cerebellum

Cell and Tissue Research

Naruse

et al. 2002

Self Cite

The pancreatic duct is the major site for the secretion of pancreatic fluid, but the pathway of water transport in this system is not known. Recently, intense signal for mRNA of aquaporin 1 (AQP1) water channels was detected in isolated rat interlobular ducts. Therefore, we performed light- and electron-microscopic (EM) immunohistochemistry for AQP1 in the rat pancreatic ducts. AQP1 immunoproducts were not observed in the acinar cells, centroacinar cells or intercalated ducts. In the smaller intralobular ducts less than 10 microm in diameter (the lumen plus duct cells), most cells were immunonegative. AQP1-positive cells appeared in intralobular ducts 10-15 microm in diameter. In small and medium-sized interlobular ducts 15-70 microm in diameter surrounded by periductal connective tissue 2-40 microm thick, most cells were AQP1 positive with various degrees of immunoreactivity. In the larger interlobular ducts, the expression of AQP1 was variable, ranging from immunopositive to negative. In the main pancreatic duct, most cells were negative for AQP1. EM immunohistochemistry of the intralobular and small interlobular ductal epithelial cells showed that the AQP1 immunoproducts were more abundant in the basolateral membrane than in the apical membrane, though they were present in both membranes. In the medium-sized interlobular ducts, AQP1 immunoproducts were distributed densely along the apical, lateral interdigitation and basal membrane of the epithelial cells. In the various sizes of interlobular ducts, immunoproducts were associated not only with the plasma membrane, but also with the caveolae and vesicle-like structures. Secretin did not induce any significant difference in AQP1 expression and cellular and subcellular localization. These results indicate that the expression and subcellular localization of AQP1 vary considerably depending on the duct size, which may reflect water transport characteristics in the different divisions of the pancreatic duct system.

Section: Capillarymentioning

confidence: 99%

Section: Preparation For Immunohistochemistrymentioning

confidence: 99%

Section: Preparation For Immunohistochemistrymentioning

confidence: 99%

See 1 more Smart Citation

Distribution of aquaporin 1 in the rat pancreatic duct system examined with light- and electron-microscopic immunohistochemistry

Cell and Tissue Research

Naruse

et al. 2002

Self Cite

“…Rat small intestines Wild-type AR rats and Wistar rats were perfused with 4% paraformaldehyde/0.2% picric acid in 0.1 M phosphate buffer pH 7.4, and processed for light microscopic immunohistochemistry as previously described (Furuya et al, 2001). 10 μm thick cryosections were incubated with methanol containing 0.3% H 2 O 2 for 30 minutes to inhibit endogenous peroxidase activity, and incubated with 10% NGS in PBS for 30 minutes.…”

Section: Immunohistochemistrymentioning

confidence: 99%

Characteristics of subepithelial fibroblasts as a mechano-sensor in the intestine: cell-shape-dependent ATP release and P2Y1 signaling

Sokabe

Journal of Cell Science

2005

Self Cite

Subepithelial fibroblasts form a cellular network just under the epithelium of the gastrointestinal tract. Using primary cultured cells isolated from rat duodenal villi, we previously found that subepithelial fibroblasts reversibly changed cell morphology between flat and stellate-shape depending on intracellular cAMP levels. In this paper, we examined cell-cell communication via released ATP and Ca2+ signaling in the cellular network. Subepithelial fibroblasts were sensitive to mechanical stress such as `touching' a cell with a fine glass rod and `stretching' cells cultured on elastic silicone chamber. Mechanical stimulations evoked Ca2+-increase in the cells and ATP-release from the cells. The released ATP activated P2Y receptors on the surrounding cells and propagated Ca2+-waves through the network. Concomitant with Ca2+-waves, a transient contraction of the network was observed. Histochemical, RT-PCR, western blotting and Ca2+ response analyses indicated P2Y1 is a dominant functional subtype. ATP-release and Ca2+ signaling were cell-shape dependent, i.e. they were abolished in stellate-shaped cells treated with dBcAMP, and recovered or further enhanced in re-flattened cells treated with endothelin. The response to ATP also decreased in stellate-shaped cells. These findings indicate cAMP-mediated intracellular signaling causes cell-shape change, which accompanies the changes in mechano- and ATP sensitivities. Using a co-culture system of neuronal cells (NG108-15) with subepithelial fibroblasts, we confirmed that mechanically induced Ca2+-waves propagated to neurons. From these findings we propose that subepithelial fibroblasts work as a mechanosensor in the intestine. Uptake of food, water and nutrients may cause mechanical stress on subepithelial fibroblasts in the villi. The ATP released by mechanical stimulation elicits Ca2+-wave propagation through the network via P2Y1 activation and also activates P2X on terminals of mucosal sensory neurons to regulate peristaltic motility.

Proc. Natl. Acad. Sci. U.S.A.

“…They were then treated with PBS containing 4% paraformaldehyde for 15 min at room temperature, rinsed with PBS, and embedded in OCT compound. The frozen sections were prepared and immunostained as described (35).…”

Section: Methodsmentioning

confidence: 99%

Caffeine activates mouse TRPA1 channels but suppresses human TRPA1 channels

Nagatomo

Kubo

2008

107

Caffeine has various well-characterized pharmacological effects, but in mammals there are no known plasma membrane receptors or ion channels activated by caffeine. We observed that caffeine activates mouse transient receptor potential A1 (TRPA1) in heterologous expression systems by Ca i 2؉ imaging and electrophysiological analyses. These responses to caffeine were confirmed in acutely dissociated dorsal root ganglion sensory neurons from WT mice, which are known to express TRPA1, but were not seen in neurons from TRPA1 KO mice. Expression of TRPA1 was detected immunohistochemically in nerve fibers and bundles in the mouse tongue. Moreover, WT mice, but not KO mice, showed a remarkable aversion to caffeine-containing water. These results demonstrate that mouse TRPA1 channels expressed in sensory neurons cause an aversion to drinking caffeine-containing water, suggesting they mediate the perception of caffeine. Finally, we observed that caffeine does not activate human TRPA1; instead, it suppresses its activity.