Document Type
Article
Language
eng
Publication Date
10-1997
Publisher
American Physiological Society
Source Publication
American Journal of Physiology - Cell Physiology
Source ISSN
0002-9513
Abstract
The functional significance of the variable expression of the smooth muscle myosin heavy chain (SM-MHC) tail isoforms, SM1 and SM2, was examined at the mRNA level (which correlates with the protein level) in individual permeabilized rabbit arterial smooth muscle cells (SMCs). The length of untethered single permeabilized SMCs was monitored during unloaded shortening in response to increased Ca2+ (pCa 6.0), histamine (1 μM), and phenylephrine (1 μM). Subsequent to contraction, the relative expression of SM1 and SM2 mRNAs from the same individual SMCs was determined by reverse transcription-polymerase chain reaction amplification and densitometric analysis. Correlational analyses between the SM2-to-SM1 ratio and unloaded shortening in saponin- and α-toxin-permeabilized SMCs (n = 28) reveal no significant relationship between the SM-MHC tail isoform ratio and unloaded shortening velocity. The best correlations between SM2/SM1 and the contraction characteristics of untethered vascular SMCs were with the minimum length attained following contraction (n = 20 and r = 0.72 for α-toxin, n = 8 and r = 0.78 for saponin). These results suggest that the primary effect of variable expression of the SM1 and SM2 SM-MHC tail isoforms is on the cell final length and not on shortening velocity.
Recommended Citation
Meer, Daniel P. and Eddinger, Thomas, "Expression of Smooth Muscle Myosin Heavy Chains and Unloaded Shortening in Single Smooth Muscle Cells" (1997). Biological Sciences Faculty Research and Publications. 596.
https://epublications.marquette.edu/bio_fac/596
Comments
Accepted version. American Journal of Physiology - Cell Physiology, Vol. 273, No. 4 (October 1997): C1259-C1266. DOI. © 2018 The American Physiological Society. Used with permission.