Ca²⁺-Sensitization of Contraction in the h1 Calponin-Deficient Smooth Muscle

Abstract

Role of h1 calponin on Ca²⁺-sensitivity of smooth muscle contraction was investigated using h1 calponin gene-deficient mice (CP−/−) and wild type mice (CP+/+). PGF_2α induced a comparable force in intact aorta of CP+/+ and CP−/−. DPB showed similar effects to PGF_2α. In membrane-permeabilized ileal smooth muscle, PDBu enhanced Ca²⁺-sensitivity of contraction comparably in CP+/+ and CP−/−. GTPγ-S showed similar effects. Our results suggest that h1 calponin does not regulate Ca²⁺-sensitivity in the contractile mechanism of smooth muscle.