ABSTRACT
After reading this chapter you should be able to:
outline the ultrastructural basis of vascular contraction (12.2);
contrast contraction in vascular and cardiac myocytes (12.1, 12.3);
outline the roles of Ca2+, K+ and Cl− channels in vascular tone regulation (12.4);
state the roles of myosin light-chain kinase (MLCK), myosin light-chain phosphatase (MLCP), phospholipase C (PLC), inositol 1,4,5 trisphosphate (IP3) and diacylglycerol (DAG) in excitation-contraction coupling (12.3, 12.5);
explain the difference between depolarization-dependent and depolarization-independent contraction (12.5);
state the role and mechanism of Ca2+-sensitization during tonic contraction (12.5);
explain how sympathetic nerve activity evokes vasoconstriction (12.5);
outline four mechanisms mediating vasodilatation (12.7).
