ROLE OF THE MEMBRANE EXCITABILITY IN MUSCLE FATIGUE

PART I

OBJECTIVES (I and II)• Methodology:

• Electrophysiology: resting Em and action potential • Measurement of ion channel activity

• Control of membrane excitability during muscle activity:

• Role of ions (Na+, K+ and Cl-)• Role of Cl- and K+ channels

INTRODUCTION

Lännergren and Westerblad, 1991

Lännergren and Westerblad, 1991

CAFFEINE

Lännergren and Westerblad, 1991

PLA: placeboCIT: ingestion of sodium citrate to create an alkalosis

PLA: placebo

CIT: ingestion of sodium citrate to create an alkalosis

PLA: placebo

CIT: ingestion of sodium citrate to create an alkalosis

DISCUSSION

y = yo e-bx

yo= V/I = Rin (input resistance, from intercept)

= 1/b (length constant, from slope)

rm = 2 Rin

EDL

SOLEUS