Portal de Periódicos da CAPES

Differential modulation of large-conductance KCa channels by PKA in pregnant and nonpregnant myometrium

1994; American Physical Society; Volume: 266; Issue: 5 Linguagem: Inglês

10.1152/ajpcell.1994.266.5.c1459

1522-1563

Guillermo J. Pérez, L. Toro,

Neuroendocrine regulation and behavior

Uterine excitability depends on ion channel activity, the expression of which is regulated by sexual hormones. We show now that the action of protein kinase A (PKA) on large-conductance calcium-activated K+ (KCa) channel activity also depends on the hormonal status. PKA-dependent phosphorylation of reconstituted KCa channels from midpregnant rats usually stimulated channel activity; in contrast, KCa channels from nonpregnant rat and human myometrium were primarily inhibited by this mechanism. Both effects were reversible by phosphatase treatment. These results suggest that one important factor modulating uterine contractility during pregnancy or the regular cycle may be the differential response of KCa channels toward PKA-induced phosphorylation.