Effect of temperature on muscarinic cholinoceptor-mediated phosphoinositide metabolism and tension generation in bovine tracheal smooth muscle

Author(s):  
EdwinR. Chilvers ◽  
MarkA. Giembycz ◽  
R.A.John Challiss ◽  
GrahamJ. Offer ◽  
StefanR. Nahorski
1992 ◽  
Vol 73 (4) ◽  
pp. 1481-1485 ◽  
Author(s):  
K. Ishida ◽  
P. D. Pare ◽  
J. Hards ◽  
R. R. Schellenberg

The in vitro mechanical properties of smooth muscle strips from 10 human main stem bronchi obtained immediately after pneumonectomy were evaluated. Maximal active isometric and isotonic responses were obtained at varying lengths by use of electrical field stimulation (EFS). At the length (Lmax) producing maximal force (Pmax), resting tension was very high (60.0 +/- 8.8% Pmax). Maximal fractional muscle shortening was 25.0 +/- 9.0% at a length of 75% Lmax, whereas less shortening occurred at Lmax (12.2 +/- 2.7%). The addition of increasing elastic loads produced an exponential decrease in the shortening and velocity of shortening but increased tension generation of muscle strips stimulated by EFS. Morphometric analysis revealed that muscle accounted for 8.7 +/- 1.5% of the total cross-sectional tissue area. Evaluation of two human tracheal smooth muscle preparations revealed mechanics similar to the bronchial preparations. Passive tension at Lmax was 10-fold greater and maximal active shortening was threefold less than that previously demonstrated for porcine trachealis by us of the same apparatus. We attribute the limited shortening of human bronchial and tracheal smooth muscle to the larger load presumably provided by a connective tissue parallel elastic component within the evaluated tissues, which must be overcome for shortening to occur. We suggest that a decrease in airway wall elastance could increase smooth muscle shortening, leading to excessive responses to contractile agonists, as seen in airway hyperresponsiveness.


1977 ◽  
Vol 233 (3) ◽  
pp. C92-C98 ◽  
Author(s):  
N. L. Stephens ◽  
R. Cardinal ◽  
B. Simmons

The effect of temperature on the isometric tetanic myogram was studied in isolated canine tracheal smooth muscle (TSM). At 37 degrees C and 27 degrees C no significant change occurred in maximum tetanic tension (PO). At 17 degrees C a significant reduction was seen Values of Q10 for contraction time (tPO) were almost halved, whereas those for rate of tension development (dP/dt) were almost doubled. The effect of the same temperatures on the force-velocity (F-v) relationships was also studied. All three F-v curves were described by the Hill equation, (P + a) (v + b) = (PO + a)b. Vmax and b decreased with decreased temperature, with Q10's demonstrating they were dependent on active processes. Finally, the decreased dP/dt of the myogram at lower temperatures was felt to be the probable result of decreased contractile element velocity because no decrease in series elastic component stiffness was demonstrable, there being instead an increase in stiffness at lower temperatures.


1994 ◽  
Vol 111 (1) ◽  
pp. 21-28 ◽  
Author(s):  
Chuen Mao Yang ◽  
Hui-Chuan Hsia ◽  
Sheng-Ping Chou ◽  
Richard Ong ◽  
Jen-Tsung Hsieh ◽  
...  

1998 ◽  
Vol 511 (3) ◽  
pp. 719-731 ◽  
Author(s):  
Yoshiki Waniishi ◽  
Ryuji Inoue ◽  
Hiromitsu Morita ◽  
Noriyoshi Teramoto ◽  
Kihachiro Abe ◽  
...  

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