Frequency-Dependent Effects of 4-Aminopyridine and Almokalant on Action-Potential Duration of Adult and Neonatal Rabbit Ventricular Muscle

1999 ◽  
Vol 33 (3) ◽  
pp. 352-359 ◽  
Author(s):  
Alejandro Elizalde ◽  
Héctor Barajas ◽  
Ricardo Navarro-Polanco ◽  
José Sánchez-Chapula
Keyword(s):  
Action Potential ◽  
Action Potential Duration ◽  
Ventricular Muscle ◽  
Frequency Dependent ◽  
Rabbit Ventricular Muscle

Preceding Stimulus Frequency-Dependent Potentiation of the Postrest Shortening of the Action Potential Duration in Rabbits.

2000 ◽  
Vol 41 (4) ◽  
pp. 481-492
Author(s):  
Naohiko Takahashi ◽  
Morio Ito ◽  
Shuji Ishida ◽  
Takao Fujino ◽  
Mikiko Nakagawa ◽  
...  
Keyword(s):  
Action Potential ◽  
Action Potential Duration ◽  
Stimulus Frequency ◽  
Frequency Dependent ◽  
Preceding Stimulus

Reduction in transmembrane Ca influx induced by the negative inotropic action of nicardipine in frog ventricular muscle

1986 ◽  
Vol 64 (7) ◽  
pp. 927-930
Author(s):  
Junna Hatae
Keyword(s):  
Mechanical Properties ◽  
Action Potential ◽  
Resting Potential ◽  
Ventricular Muscle ◽  
Inotropic Action ◽  
Frequency Dependent ◽  
High Frequencies ◽  
Dihydropyridine Derivative

The effects of nicardipine, a new 1,4-dihydropyridine derivative, on electrical and mechanical properties of frog ventricular muscle were examined. Nicardipine (3 × 10−7 M) reduced the twitch tension, and this reduction was frequency dependent, and considerable, in case of high frequencies. The resting potential was not affected by nicardipine (3 × 10−7 M), but the plateau height of the action potential was decreased and the duration of the action potential was shortened. The suppression of this plateau height was frequency dependent. The nicardipine-induced suppression of tension and action potential could be almost completely antagonized by raising the concentration of [Ca]o or by applying isoprenaline (8 × 10−7 M). These results suggest that the negative inotropic action of nicardipine is induced mainly by a reduction in the transmembrane Ca influx.

Sign in / Sign up

Export Citation Format

Share Document