Effect of partial outlet obstruction of the rabbit urinary bladder on ryanodine binding to microsomal membranes.
1. Partial outlet of obstruction of the rabbit urinary bladder results in a significant increase in the ability of ryanodine to inhibit field stimulated contraction. The current study determined the effect of outlet obstruction on ryanodine binding to microsomal membranes. 2. The results demonstrate: (i) Ryanodine binding is linear showing one set of ryanodine binding sites (Bmax = 28 +/- 3.5 fmol/mg protein; Kd = 4.2 nM). (ii) Total ryanodine binding was slightly increased at 1 and 3 day following obstruction. (iii) Binding increased approx 4-fold at 5 and 7 days post obstruction. (iv) No change in the Kds were noted at any time period. 3. The results of these studies indicate that smooth muscle hypertrophy secondary to partial outlet obstruction induces a marked increase in the role of intracellular calcium in the mediation of the contractile response to field stimulation.
Levin
R M
RM
Division of Urology, University of Pennsylvania School of Medicine, Philadelphia 19104.
Levin
S S
SS
Zderic
S A
SA
Saito
M
M
Yoon
J Y
JY
Wein
A J
AJ
D000818:Animals; D002118:Calcium / Q000378:metabolism; D006984:Hypertrophy / Q000378:metabolism; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism*; D016014:Linear Models; D008297:Male; D008861:Microsomes / Q000378:metabolism*; D009119:Muscle Contraction / Q000502:physiology; D011817:Rabbits; D012433:Ryanodine / Q000378:metabolism*; D001748:Urinary Bladder Neck Obstruction / Q000378:metabolism* / Q000473:pathology
D012433:Ryanodine; D002118:Calcium