Search

The P2X[sub7] cell surface receptor is responsible for adenosine triphosphate-dependent lysis of immune cells following the formation of non-selective membrane pores. This study examined changes in P2X[sub7] receptor distribution following agonist treatment. Human THP-1 monocytes were exposed to the agonist 2′-3′-O-(4-benzoylbenzoyl) adenosine 5′-triphosphate for 1—40 min after which P2X[sub7] receptors were immunogold labelled. The number and distribution of P2X7 receptors on the cell membrane were quantified using transmission electron microscopy. Increasing the time of agonist exposure resulted in clustering of P2X[sub7] receptors, a decrease in individual P2X[sub7] receptors and no change in the total number of P2X[sub7] receptors. These results suggest that pore formation does not involve further insertion or initial movement of receptors in the membrane but that P2X[sub7] receptors do cluster together after prolonged activation. [ABSTRACT FROM AUTHOR]

Adenosine 5′-triphosphate (ATP) is known to play a significant role as a neurotransmitter in smooth muscle. There is evidence to show that ATP can cause bladder contractions and may also be involved in the processing of sensory information in the urinary bladder. These effects are likely to be mediated by P2X receptors, namely P2X[sub 1] and P2X[sub 3] , respectively. This study set out to investigate their distribution in rat and human urinary bladders. P2X[sub 1] receptor immunoreactivity was found on detrusor muscle fibres and P2X[sub 3] receptor immunoreactivity was found in the urothelium of both species. This is the first demonstration of a non-neuronal localisation for P2X[sub 3] receptors. No clear evidence was found for the presence of P2X[sub 3] receptors on calcitonin gene-related peptide-containing sensory nerves and therefore P2X[sub 3] receptors may not have a direct role in the mediation of sensory responses to ATP in the urinary bladder.Copyright © 2001 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The P2X(7) cell surface receptor is responsible for adenosine triphosphate-dependent lysis of immune cells following the formation of non-selective membrane pores. This study examined changes in P2X(7) receptor distribution following agonist treatment. Human THP-1 monocytes were exposed to the agonist 2'-3'-O-(4-benzoyl-benzoyl) adenosine 5'-triphosphate for 1-40 min after which P2X(7) receptors were immunogold labelled. The number and distribution of P2X(7) receptors on the cell membrane were quantified using transmission electron microscopy. Increasing the time of agonist exposure resulted in clustering of P2X(7) receptors, a decrease in individual P2X(7) receptors and no change in the total number of P2X(7) receptors. These results suggest that pore formation does not involve further insertion or initial movement of receptors in the membrane but that P2X(7) receptors do cluster together after prolonged activation., (Copyright 2003 S. Karger AG, Basel)