Smooth Myocytes - Tissue Functioning and Remodeling in the Circulatory and Ventilatory Systems - page 418

Table 8.12. Main features of certain SMC ion carriers.

Potassium carriers

Inward rectifier Mainly in arterioles;

opening at resting potential;
outward current

Delayed rectifier Repolarization;

(outward rectifier) slow activation beyond − 30 mV

ATP-gated Opening by low [ATP], increased [ADP], [GDP],

adenosine A 1 receptors, and H + ;
low basal activity;
stimulation by the cAMP-PKA axis

Ca 2 + -gated Stimulation by cytosolic Ca 2 +

and by depolarization;
high conductance;
repolarization;
NO effector

Calcium carriers

Voltage-gated Influx;

high (Ca V 1) or low (Ca V 3) conductance;
long (Ca V 1) or transient (Ca V 3) opening;
abundant in small arteries (Ca V 1)

Receptor-operated Non-selective cation channel;

effector of NAd, ATn, vasopressin, 5HT, histamine;
linked to α 1-adrenoceptor and ATPR

Chloride carriers

Ca 2 + -gated Efflux

Modulation of basal potential

Non-selective cation channel
Permeability to Ca 2 + ,Na + ,K +
Stimulation by DAG
Depolarization

Stretch-sensitive cation channel

Permeability to Ca 2 + ,Na +
Activation of voltage-gated Ca 2 + channel
Depolarization

1, and serpin-E2, or protease nexin-1. The synthesis and secretion of TIMPs and
PAI by vascular smooth myocytes are mainly controlled by the TGF

β

-SMAD

pathway [ 745 ].
In arterial aneurysms and dissections, vascular smooth myocytes can express
and release peptidases such as matrix metallopeptidases [ 745 ]. Vascular smooth