P2X-purinoceptors in the heart: actions of ATP and UTP
Autor: | Guglielmina Froldi, Pier Andrea Borea, Eugenio Ragazzi, Laura Caparrotta, Alessandro Chinellato, Katia Varani |
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Jazyk: | angličtina |
Rok vydání: | 1997 |
Předmět: |
P2Y receptor
Ca Guinea Pigs chemistry.chemical_element Uridine Triphosphate Pharmacology Calcium UTP Binding Competitive General Biochemistry Genetics and Molecular Biology Dantrolene Guinea pig Adenosine Triphosphate Nifedipine Positive inotropism medicine Animals heterocyclic compounds General Pharmacology Toxicology and Pharmaceutics Rats Wistar Receptor P2X-purinoceptors Ryanodine receptor Receptors Purinergic P2 β-methylene ATP Myocardium General Medicine ++ Stimulation Chemical Rats ATP Kinetics chemistry Biochemistry Inotropism [ 3 H]α β-methylene ATP inhibitors H]α medicine.drug Muscle Contraction |
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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