Smooth muscle excitation

Excitation-contraction coupling in airway smooth muscle.

Excitation-contraction (EC) coupling in striated muscles is mediated by the cardiac or skeletal muscle isoform of voltage-dependent L-type Ca(2+) channel (Ca(v)1.2 and Ca(v)1.1, respectively) that senses a depolarization of the cell membrane, and in response, activates its corresponding isoform of intracellular Ca(2+) release channel/ryanodine receptor (RyR) to release stored Ca(2+), thereby in...

Secondary excitation of intestinal smooth muscle.

1. A period of stimulation of intrinsic or extrinsic nerves to intestinal muscle is often followed by a secondary contraction. In the present work, the basis for such secondary contractions in the longitudinal muscle of the large bowel of guinea-pigs and rabbits was examined.2. In general, the action of cholinergic nerves did not contribute significantly to the secondary contractions. Concentra...

Temporal aspects of excitation-contraction coupling in airway smooth muscle.

In airway smooth muscle (ASM), ACh induces propagating intracellular Ca2+ concentration ([Ca2+]i) oscillations (5-30 Hz). We hypothesized that, in ASM, coupling of elevations and reductions in [Ca2+]i to force generation and relaxation (excitation-contraction coupling) is slower than ACh-induced [Ca2+]i oscillations, leading to stable force generation. When we used real-time confocal imaging, t...

Electric Stimulation and Conduction of Excitation in Smooth Muscle

Excitation coupling in muscle.

How much mechanical activity follows a membrane depolarisation of known amplitude and duration? For the steady state case we have the result of Hodgkin (1958), significant in view of what follows, that contracture tension varies for low levels approximately as the sixth power of the depolarisation. To answer the more difficult question involving time, one might think that something like "voltag...