Changes in intracellular Ca2+ by activation of P2 receptors in submucosal neurons in short-term cultures.
Electrophysiological and Ca2+ microfluorimetric techniques were used to characterize the pharmacological profile of the P2 receptors expressed in submucosal neurons and the changes in intracellular Ca2+ associated with activation of these receptors. ATP caused a fast and slow membrane depolarizations during intracellular recordings. ATP induced a rapid inward current during whole-cell experiments. Receptors mediating the inward current and fast depolarization have the same pharmacological profile and these ATP responses were more sensitive to pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid than Basilen BlueE-3G, and potentiated by suramin. The slow depolarization was not blocked by these P2 receptor antagonists, pertussis toxin, or KT5720 (protein kinase A inhibitor). N-ethylmaleimide or protein kinase C inhibitors (staurosporine and calphostin) blocked this depolarization. ATP induced complex multi-phasic Ca2+ transients in most neurons, classified as fast, slow, or mixed fast/slow responses. In conclusion, the fast and slow Ca2+ responses were mediated by respective activation of P2X and P2Y receptors and were associated with fast and slow depolarizations, respectively.
Barajas-López
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Department of Anatomy and Cell Biology, Queen's University, 9th Floor Botterell Hall, Kingston, ON K7L3N6, Canada. barajasc@meds.queensu.ca
Espinosa-Luna
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Christofi
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D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D018048:Receptors, Purinergic P2 / Q000187:drug effects* / Q000502:physiology; D058469:Receptors, Purinergic P2X; D058472:Receptors, Purinergic P2Y1; D013368:Submucous Plexus / Q000187:drug effects* / Q000502:physiology
D010975:Platelet Aggregation Inhibitors; D018048:Receptors, Purinergic P2; D058469:Receptors, Purinergic P2X; D058472:Receptors, Purinergic P2Y1; C077792:pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid; D011732:Pyridoxal Phosphate; D000255:Adenosine Triphosphate; D002118:Calcium