TY - JOUR

T1 - The kinetics of monazomycin-induced voltage-dependent conductance

T2 - I. Proof of the validity of an empirical rate equation

AU - Muller, Robert U.

AU - Orin, Gary

AU - Peskin, Charles S.

PY - 1981/8/1

Y1 - 1981/8/1

N2 - Monazomycin (a positively-charged, polyene-like antibiotic) induces a strongly voltage-dependent conductance in thin lipid membranes when added to one of the bathing solutions. We show here that the kinetics of conductance changes after a step of membrane potential are only superficially similar to the kinetics of the potassium gating system of squid giant axons, in that the beginning of conductance increases are growth functions of the time, as opposed to power functions of the time. We find that the rate constant (reciprocal of the time constant) of the growth varies with the ~2.6 power of the monazomycin concentration. The rate constant also varies exponentially with membrane potential such that an e-fold change is associated with a 10-11 mV change of membrane potential. We show that solutions of a simple differential equation are able to reproduce the actual conductance changes almost exactly. In the accompanying paper (Muller and Peskin. 1981.J. Gen. Physiol. 78:201-229), we derive the differential equation from a molecular model and use the theoretical equation so obtained to investigate the gating current of this system and to predict an interesting form of memory.

AB - Monazomycin (a positively-charged, polyene-like antibiotic) induces a strongly voltage-dependent conductance in thin lipid membranes when added to one of the bathing solutions. We show here that the kinetics of conductance changes after a step of membrane potential are only superficially similar to the kinetics of the potassium gating system of squid giant axons, in that the beginning of conductance increases are growth functions of the time, as opposed to power functions of the time. We find that the rate constant (reciprocal of the time constant) of the growth varies with the ~2.6 power of the monazomycin concentration. The rate constant also varies exponentially with membrane potential such that an e-fold change is associated with a 10-11 mV change of membrane potential. We show that solutions of a simple differential equation are able to reproduce the actual conductance changes almost exactly. In the accompanying paper (Muller and Peskin. 1981.J. Gen. Physiol. 78:201-229), we derive the differential equation from a molecular model and use the theoretical equation so obtained to investigate the gating current of this system and to predict an interesting form of memory.

UR - http://www.scopus.com/inward/record.url?scp=0019466076&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0019466076&partnerID=8YFLogxK

U2 - 10.1085/jgp.78.2.171

DO - 10.1085/jgp.78.2.171

M3 - Article

C2 - 7276907

AN - SCOPUS:0019466076

SN - 0022-1295

VL - 78

SP - 171

EP - 200

JO - Journal of General Physiology

JF - Journal of General Physiology

IS - 2

ER -