P2X-purinoceptors in the heart: actions of ATP and UTP

Autor: Guglielmina Froldi, Pier Andrea Borea, Eugenio Ragazzi, Laura Caparrotta, Alessandro Chinellato, Katia Varani
Jazyk: angličtina
Rok vydání: 1997
Předmět:
Popis: Positive inotropic effects of ATP and UTP (1 microM - 1mM) were studied in isolated rat and guinea pig cardiac tissues. The potency order obtained was ATPUTP in both species, suggesting possible interaction with P2X-purinoceptors. Binding studies using [(3)H]alpha,beta-methylene ATP as marker of P2X-purinoceptors revealed two receptor sites: one high-, the other low-affinity, in atria and ventricles from rat and guinea pig. Both ATP and UTP were found to bind high-affinity sites of [(3)H]alpha,beta-methylene ATP. The effects of various calcium inhibitors such as nifedipine, dantrolene, ryanodine and TMB-8 on positive inotropic effects induced by ATP and UTP were also studied. The results suggest that ATP and UTP may increase inotropism by interaction with P2X-purinoceptors by means of a calcium-dependent mechanism.
Databáze: OpenAIRE
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