[Cholinergic action of Bay K-8644 on the rat heart sinus node automaticity]. / Acción colinergica de Bay K-8644 sobre el automatismo sinusal en corazon de rata.
Rev Med Chil
; 121(7): 725-8, 1993 Jul.
Article
em Es
| MEDLINE
| ID: mdl-7507595
The actions of different concentrations of a dihydropyridine agonist (Bay K-8644) on rat heart sinus node automaticity and their interactions with atropine, were studied. The experiments were performed using a portion of the right atrium that contained the sinus node, perfused with Tyrode's solution at 37 degrees C and registering the action potentials with intracellular microelectrodes (Ag-KCL). The series of Bay K with or without atropine were perfused during 10 min. Atropine, 1 x 10(-5) M, did not change sinus frequency after 30 min of perfusion (237 +/- 6 to 229 +/- 7 action potentials/min; n = 24). Bay K, 2.8 x 10(-8) M (10 ug/L) did not change sinus frequency (240 +/- 9 to 246 +/- 12; n = 8, but in the presence of atropine, caused an increment (225 +/- 7 to 256 +/- 12 p < 0.05). Bay K, 7 x 10(-8) M (25 ug/L) and 1.4 x 10(-7) M (50 ug/L, caused an increase in sinus frequency (237 +/- 5 to 279 +/- 15; n = 9 p < 0.05 and 254 +/- 6 to 291 +/- 6; n = 6 p < 0.05 respectively) that occurred sooner in the presence of atropine. It is concluded that Bay-K has a cholinergic effect that interferes with its positive chronotropic action, specially at low concentrations.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Nó Sinoatrial
/
Éster Metílico do Ácido 3-Piridinacarboxílico, 1,4-Di-Hidro-2,6-Dimetil-5-Nitro-4-(2-(Trifluormetil)fenil)
Limite:
Animals
Idioma:
Es
Revista:
Rev Med Chil
Ano de publicação:
1993
Tipo de documento:
Article
País de afiliação:
Chile
País de publicação:
Chile