Abstract
An in vitro model of smooth muscle stretch was developed to study mechanical stimulus as a possible mediator of visceral smooth muscle growth and differences in the growth response of smooth muscle from young and old animals. De novo DNA synthesis as measured by the aphidicolin-sensitive specific activity of DNA was used as an index of cell growth. Compared with old tissue, the rate of aphidicolin-sensitive DNA synthesis in smooth muscle from young animals was 3-5 and 1.5-2 times greater in bladder and taenia coli, respectively. Stretch of bladder muscle and taenia coli strips from young animals for 6 h increased the aphidicolin-sensitive specific activity of DNA 3-fold (P < 0.01) and 1.5-fold (P < 0.01), respectively. Tissue from old animals, however, under the same conditions increased the rate of aphidicolin-resistant DNA synthesis, possibly implying DNA repair. Autoradiography showed only labeled myocyte nuclei. These results indicate that homeostatic mechanisms modulating myocyte growth in visceral smooth muscle can respond to mechanical stimulus in the absence of other trophic factors.
Original language | English (US) |
---|---|
Pages (from-to) | R895-R900 |
Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
Volume | 262 |
Issue number | 5 31-5 |
DOIs | |
State | Published - 1992 |
Externally published | Yes |
Keywords
- DNA synthesis
- detrusor
- isotonic tension
- taenia coli
ASJC Scopus subject areas
- Medicine(all)