Effects of phasic and tonic activation on contraction dynamics in smooth muscle.

Responses to isotonic quick releases of rabbit urinary bladder strips and rat portal veins activated by AC-stimulation and K+-high medium were studied. The AC stimulation was adjusted to give the same tension as th K+-contractures. Releases were performed at peak of the contractions (which was attained after 1.5-4.5 s AC-stimulation or 2-3 min in K+-high… (More)