skip to main content
Idioma:

Comparison of the Effects of Several Calcium Antagonistic Drugs (Slow-Channel Blockers) on the Electrical and Mechanical Activities of Guinea Pig Papillary Muscle

Molyvdas, Paschalis-Adam ; Sperelakis, Nick

Journal of cardiovascular pharmacology, 1983-01, Vol.5 (1), p.162-169 [Periódico revisado por pares]

United States: Lippincott-Raven Publishers

Texto completo disponível

Citações Citado por
  • Título:
    Comparison of the Effects of Several Calcium Antagonistic Drugs (Slow-Channel Blockers) on the Electrical and Mechanical Activities of Guinea Pig Papillary Muscle
  • Autor: Molyvdas, Paschalis-Adam ; Sperelakis, Nick
  • Assuntos: action potential ; Action Potentials - drug effects ; Animals ; Calcium Channel Blockers - pharmacology ; Electrophysiology ; Female ; Guinea Pigs ; heart ; Heart - drug effects ; Isoproterenol - pharmacology ; Male ; mesudipine ; Myocardial Contraction - drug effects ; nifedipine ; Nifedipine - analogs & derivatives ; Nifedipine - pharmacology ; Papillary Muscles - drug effects ; Verapamil - pharmacology
  • É parte de: Journal of cardiovascular pharmacology, 1983-01, Vol.5 (1), p.162-169
  • Notas: ObjectType-Article-2
    SourceType-Scholarly Journals-1
    ObjectType-Feature-1
    content type line 23
  • Descrição: SUMMARYThe effects of mesudipine (an analog of nifedipine), in comparison with those of verapamil and nifedipine, were studied on the normal fast action potentials (APs), the slow APs, and the contractions of guinea pig papillary muscles. In papillary muscles perfused with normal Tyrode solution, mesudipine depressed (10 and 10M) and abolished (10M) contractions within 10–12 min. The maximal upstroke velocity (+ max) and overshoot of the fast APs were not affected, whereas the AP duration (at 50 and 90% repolarization, APD50, APD90) was shortenedAPD90 by 30% and APD50 by 36% at 10 M. In order to determine the effect of mesudipine on the slow APs, the fast Na channels were inactivated by partial depolarization (to about −40 mV) by perfusing with 25 m M K-Tyrode solution. Slow-rising overshooting APs and contractions were elicited on stimulation when iso-proterenol (10M), theophylline (10M), or histamine (10M) were added. The slow-channel blockers verapamil (5 × 10M) and nifedipine (10M) completely blocked the slow APs. Mesudipine, at 4 × 10M, depressed + max, amplitude, and duration of the isoproterenol-induced slow APs, whereas at 10M, excitability was abolished within 12 min. The contractions accompanying the slow APs were depressed by mesudipine in a parallel manner. The effect of mesudipine on the slow APs was reversed by washout of the drug after 20–40 min. The dose/response curve for the mesudipine effect was shifted to the right in high Ca concentration (5.4 m M). Lowering the stimulation frequency from 0.5 Hz (usual drive rate) to 0.1 Hz restored the slow APs blocked by 10M mesudipine (less than 20 min); after 20 min, the mesudipine block was independent of frequency. Mesudipine completely abolished the histamine-induced slow APs at 10M and the theophylline-induced slow APs at 3 × 10 M. The results indicate that mesudipine has Ca slow-channel blocking properties. This effect is not mediated by β-adrenergic receptor antagonism. Mesudipine has about the same potency as nifedipine and is about 10 times more potent than verapamil.
  • Editor: United States: Lippincott-Raven Publishers
  • Idioma: Inglês
Links
Voltar para lista de resultados
Ir para página anteriorAnterior Resultado  2 AvançarIr para próxima página

  • Realização: ABCD-USP USP   Logos de Redes Sociais: Freepik

Buscando em bases de dados remotas. Favor aguardar.