Search

The field of cholecystokinin (CCK) stimulation of exocrine pancreatic secretion has experienced major changes in the recent past. This review attempts to summarize the present status of the field. CCK production in the intestinal I cells, the molecular forms of CCK produced and subsequently circulated in the blood, the presence or absence of CCK receptors on the isolated pancreatic acinar cells and the associated signaling for acinar cell secretion, and the actual circuits and sites of action for CCK regulation of exocrine pancreatic secretion in vivo are reviewed in different animal species with an emphasis on birds, rodents, and humans. Clear differences in the relative importance of neural and direct modes of CCK action on pancreatic acinar cells were identified. Rodents seem to be endowed with both modes of action, whereas in humans the neural mode may predominate. In birds, such as duck, the direct mode needs further assistance from pituitary adenylate cyclaseactivating peptide/VIP receptors. However, much further work needs to be directed to the neural mode to map out all sites of CCK action and details of the full circuits, and we foresee a major revival for this field of research in the near future. pancreatic acinar cells; vagal afferent nerves; plasma cholecystokinin concentration; species specificity

Arsenic (As) is a carcinogen and it is ubiquitous in the environment. Its accumulation in plants can enter the food chain, thereby causing adverse impacts on human health. Based on studies using Xenopus oocytes, engineered microbes, and model plants, aquaporins play key roles in arsenite (AsIII) passage across the cell membrane. Herein, we summarized the roles of aquaporins in AsIII uptake, transport, and accumulation. The coupling action between polar-localized aquaporins and positive transporters probably explains the efficient As transport mediated by bi-directional channels. The expression of aquaporins is regulated at both transcriptional and post-transcriptional levels via microRNAs. However, in response to As, the proteins can be modified through phosphorylation and be degraded via the ubiquitin 26S proteasome system. Further, a proposed model comprising reactive oxygen species, Ca, Ca-dependent kinases, and transcriptional factors is constructed to reveal the signaling pathways and aquaporins' responses to As in model plants. We also provided strategies to identify and investigate putative aquaporins in plants. Identification and modification of aquaporins' residues critical for their substrate selectivity, and optimization of their expression pattern by employing appropriate promoters can be employed to reduce As accumulation in crops. Based on the characteristics of their functions and expression patterns, it is promising to employ aquaporins for genetic-engineering of crops to reduce As content and increase food safety. [ABSTRACT FROM AUTHOR]

The field of cholecystokinin (CC K) stimulation of exocrine pancreatic secretion has experienced major changes in the recent past. This review attempts to summarize the present status of the field. CCK production in the intestinal I cells, the molecular forms of CCK produced and subsequently circulated in the blood, the presence or absence of CCK receptors on the isolated pancreatic acinar cells and the associated signaling for acinar cell secretion, and the actual circuits and sites of action for CCK regulation of exocrine pancreatic secretion in vivo are reviewed in different animal species with an emphasis on birds, rodents, and humans. Clear differences in the relative importance of neural and direct modes of CCK action on pancreatic acinar cells were identified. Rodents seem to be endowed with both modes of action, whereas in humans the neural mode may predominate. In birds, such as duck, the direct mode needs further assistance from pituitary adenylate cyclase-activating peptide/VIP receptors. However, much further work needs to be directed to the neural mode to map out all sites of CCK action and details of the full circuits, and we foresee a major revival for this field of research in the near future. [ABSTRACT FROM AUTHOR]

Deals with perspectives on healthcare in the context of Chinese culture. Social structure and values of the Chinese; Influence of religion on public health; Health beliefs and practices.