Effects of UTP on Na+, Cl- and K+ transport in primary cultures from human sweat gland coils

Cellular Distribution and Functions of P2 Receptor Subtypes in Different Systems

This review is aimed at providing readers with a comprehensive reference article about the distribution and function of P2 receptors in all the organs, tissues, and cells in the body. Each section provides an account of the early history of purinergic signaling in the organ?cell up to 1994, then summarizes subsequent evidence for the presence of P2X and P2Y receptor subtype mRNA and proteins as well as functional data, all fully referenced. A section is included describing the plasticity of expression of P2 receptors during development and aging as well as in various pathophysiological conditions. Finally, there is some discussion of possible future developments in the purinergic signaling field.

Determination of chloride efflux by X-ray microanalysis versus MQAE-fluorescence

The importance of chloride channels for the cell is demonstrated by a number of serious human diseases that are due to mutations in chloride channels. The most well-known of these diseases is cystic fibrosis. Investigations into the mechanisms of the disease and possible treatments require the study of chloride fluxes at the level of individual cells. The present study compares two methods for studies of chloride transport: X-ray microanalysis and MQAE fluorescence with image analysis. As an experimental system, the cAMP-activated chloride channel in cultured respiratory epithelial cells was chosen. Both methods showed that stimulation with the cAMP-elevating agents forskolin and IBMX decreased the chloride content of the cells by about 20-27%. Inducing a driving force for chloride by replacing extracellular chloride by nitrate resulted in a chloride efflux that was significantly increased in the presence of forskolin and IBMX. This study shows that X-ray microanalysis and MQAE fluorescence are adequate and comparable methods for measuring cAMP-dependent chloride transport in individual cells.