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June 1, 1970Circulation ResearchOpen Access

Electrophysiological and Beta-Receptor Blocking Effects of MJ 1999 on Dog and Rabbit Cardiac Tissue

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Why the study?

Does MJ 1999 alter electrophysiological properties and beta-receptor activity in dog and rabbit cardiac tissue?

Population

Rabbit right atrial preparations, canine Purkinje fiber preparations, canine ventricular muscle, and dogs…

Comparison

MJ 1999 vs Control conditions (baseline)

Design

Preclinical

Authors

HSHarold C. StraussJBJ. Thomas BiggerBHBrian F. Hoffman

Discussion

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Overview

Supports class III-like effects in animal cardiac tissue; leaves open translation to human antiarrhythmic use.

Key Points

  • This research investigates the electrophysiological effects of MJ 1999 on cardiac tissues from rabbits and dogs.
  • Studied electrophysiological changes in rabbit right atrial and canine Purkinje fibers after exposure to MJ 1999
  • Evaluated action potential duration and effective refractory period in Purkinje fibers and ventricular muscle fibers
  • Administered MJ 1999 at concentrations ranging from 1 x 10 -9 M to 1 x 10 -2 M
  • MJ 1999 increased action potential duration in Purkinje fibers from 325 msec to 470 msec and effective refractory period from 277 msec to 404 msec at 1 x 10 -3 M
  • In ventricular muscle fibers, action potential duration increased from 230 msec to 281 msec and effective refractory period from 223 msec to 267 msec with MJ 1999
  • Effects on repolarization and refractoriness vary significantly from those of drugs like quinidine and procainamide.

Structured PICO

Does MJ 1999 alter electrophysiological properties and beta-receptor activity in dog and rabbit cardiac tissue?

P
Population
Rabbit right atrial preparations, canine Purkinje fiber preparations, canine ventricular muscle, and dogs with atrioventricular block
I
Intervention
MJ 1999 (1 x 10^-9 M to 1 x 10^-2 M in vitro; 2.0 mg/kg in vivo)
C
Comparator
Control conditions (baseline)
O
Outcome
Electrophysiological parameters including action potential duration (APD), effective refractory period (ERP), resting potential, and phase 0 characteristicssurrogate

MJ 1999 prolongs action potential duration and effective refractory period in cardiac tissue without affecting phase 0 depolarization, distinguishing its electrophysiological profile from quinidine, procainamide, and lidocaine.

Cite This Study

Strauss et al. (1970) studied this question.

synapsesocial.com/papers/6a20799014cb6ef00ff48d56https://doi.org/10.1161/01.res.26.6.661
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