CHAPTER 33 



Effects of ions on vascular smooth muscle 1 



SYDNEY M . FRIEDMAN 

 CONSTANCE L. FRIEDMAN 



Department of Anatomy, The University of 

 British Columbia, Vancouver, Canada 



CHAPTER CONTENTS 



Introduction 



General Physical Chemistry of Ions 

 Osmotic equilibrium 

 Ion size 

 Ion activity 

 Ion mobility 



Ion penetrability or membrane permeability 

 Special Properties of Ions in Biological Systems 

 Donnan equilibrium 



Electrochemical gradients and membrane potentials 

 Special Properties of the Physiologically Important Ions 

 Classification and Critical Appraisal of Methods 



Studies of Vascular Smooth Muscle Tension Associated 

 with Manipulation of the Milieu 

 Measurement of diastolic blood pressure 

 Measurement of peripheral resistance in regional vascular 



beds 

 Measurement of tension in the vascular strip or ring or in 

 an analogous smooth muscle strip 

 Studies of the Milieu During Manipulation of Vascular or 

 Analogous Smooth Muscle Tension 

 Measurement of extracellular and/or intracellular ions 



and water 

 Measurement of osmotic pressure and pH 

 Electrical measurements 



Continuous monitoring of Na or K. ion activity 

 Role of Sodium and Potassium in Vascular Smooth Muscle 

 Tension 

 Evidence from Studies of Diastolic Blood Pressure or 

 Reactivity 

 General relation of Na and K to clinical and experimental 



hypertension 

 Effects of varying Na and K. intake or loss on blood 

 pressure 

 Evidence from Studies of Tension or Reactivity of Vascular 

 or Analogous Tissue 

 Effects of manipulation of Na in the medium 

 Effects of manipulation of K in the medium 



1 Submitted for publication December ->o, i960. 



Evidence From Studies of Resistance in Regional Vascular 

 Beds 

 Effects of Na infusions 

 Effects of K infusions 

 Evidence from Measurement of Na and K in Relation to 

 Blood Pressure 

 Measurement of Na and K in chronic hypertension or 



hypotension 

 Measurement of Na and K. in acute hypertension or 

 hypotension 

 Evidence from Studies of the Relation of Electrical Activity 

 to Tension in Vascular or Analogous Tissues 

 Role of Calcium and Magnesium in Vascular Smooth Muscle 

 Tension 

 Calcium 

 Magnesium 

 Role of H + and OH" in Vascular Smooth Muscle Tension 

 Role of Anions in Vascular Smooth Muscle Tension 

 Theoretical Interpretations 

 Summary 



INTRODUCTION 



General Physical Chemistry of Ions 



We are here concerned only with pointing out in 

 simplified form the basic physical-chemical features 

 of ions and the manner in which these affect their 

 role in biological processes. For detailed treatment of 

 this subject the reader is referred to standard chemistry 

 texts as well as to the basic articles of Conway (31, 

 32), Hodgkin (112) and Shanes (182, 183). 



osmotic equilibrium. We may begin by considering 

 osmotic pressure to be the equivalent of the mechanical 

 pressure which must be applied to a solution to 

 prevent osmosis of the surrounding solvent into the 

 solution through the membrane. It is, therefore, not 



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