Contraction in molluscan smooth muscle

Calcium movements during contraction in molluscan smooth muscle, and the loci of calcium binding and release.

1. Conventional **Ca efflux studies of Buccinum and Neptunia pharangeal retractor and columella muscles revealed the presence of a fast and a slow calcium compartment. KCl-induced depolarization caused a stimulation of the *Ca efflux from the slow compartment, suggesting that this compartment may be related to calcium diffusion from intracellular sources. 2. Fine structural studies showed a lac...

Tonic contraction and the control of relaxation in a chemically skinned molluscan smooth muscle

The same functional states that characterize the living anterior byssus retractor muscle (ABRM) from Mytilus edulis can be initiated in the saponin-treated (chemically skinned) muscle preparation under controlled biochemical conditions. A tonic contraction was induced if the concentration of free Ca2+ was above approximately 10(7) M in the presence of Mg2+ and ATP. Maximum tension development w...

Dynamics of smooth muscle contraction

Photolysis of caged calcium (Nitr5, Calbiochem®) can be used to studycalcium dependent processes such as excitation-contraction coupling andmuscular mechanics. Expensive high energy light sources are routinely used forUV light exposure; this study describes an alternative low cost Xenon flash unitconstmcted in our laboratOlY. A 300 J short arc Xenon flash lamp (Heimarl1l®)wa...

Pharmacological properties of acetylcholine receptor in molluscan smooth muscle.

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...