The P2X7 ATP receptor in the kidney: a matter of life or death?

P2X7 is an intriguing membrane receptor for the extracellular nucleotide ATP, which functions as a ligand-gated ion channel; it can activate cell membrane permeabilization and also has a wide range of downstream signaling pathways, including mediation of inflammatory responses and modulation of cell turnover. Despite recent identification of P2X7 receptor protein in the renal tract, the biological and potential pathological functions of this receptor and its signaling cascades in the kidney are not yet fully understood. P2X7 receptor protein is expressed in normal kidney development, predominantly in the condensing mesenchyme, and later in the maturing and adult derivatives of the ureteric bud. Glomerular expression of the molecule is scarce in normal kidney, but is upregulated in chronic and inflammatory conditions, suggesting a role in the inflammatory response or in repair and remodeling in these settings. P2X7 receptor expression in the adult collecting ducts of murine kidney, as well as the collecting duct cysts in autosomal recessive polycystic kidney disease, has been described and agonists of the receptor can modulate the development of renal cysts in an in vitro model of cyst formation derived from the cpk/cpk mouse. Further investigation of the function of the P2X7 receptor in normal and abnormal kidneys might lead to novel therapeutic targets in a wide range of renal diseases.

P2 receptors in the kidney.

Our understanding of the actions of extracellular ATP in controlling kidney function via stimulation of P2 receptors is still at an early stage. Recently, several groups, including our own, have begun to address this subject: in this brief review, we discuss some of these effects and speculate on likely function of extracellular nucleotides in the kidney.

Comparing child-rearing practices in parents of children with cancer and parents of healthy children.

This nonexperimental, descriptive study identified parenting behaviors and differences in the reported child-rearing practices between parents of children diagnosed with cancer and parents of healthy children. Two groups of parents were included: 58 parents of children diagnosed with cancer at a large urban children's cancer center and 58 parents of healthy children. The total group of parents ranged from 22 to 58 years with 35.7 and 35.9 years as the mean ages of the two groups. A variety of races were included among the parents and educational backgrounds ranged from high school and vocational to graduate/ doctoral degrees. Each child with cancer selected a healthy friend of the same age, sex, and race who served as their healthy counterpart for this study. Each of these child's parents were then involved in the data collection process. Data were collected over a 2-month period using the Child-Rearing Practices Report (CRPR) in the Q-sort format, in which the parent sorted 91 cards containing 91 items dealing with child-rearing. Items were compared between the two groups using two-tailed t-tests. Using a significance level of alpha = .02, 11 significant differences were found between the two groups in the domains of parental expectations, discipline, expression of emotion, parental concern/worry, and overprotectiveness. In conclusion, the primary types of items that shared or demonstrated significant differences between the two groups of parents were those dealing with discipline and overprotectiveness issues. The items responded to most significantly different were, "I tend to spoil my child" and "I worry about the health of my child," with the parents of children with cancer consistently rating these as more descriptive of them than the parents of healthy children did. Finally, this study suggested that the time of the child's diagnosis with cancer also affected the parents' reported child-rearing practices.