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Structure and mechanics of growing arterial microvessels from hypertrophied urinary bladder in the rat

Boels, P J; Arner, Anders LU ; Malmqvist, Ulf LU and Uvelius, Bengt LU (1994) In Pflügers Archiv 426(6). p.506-515
Abstract
Rat bladder hypertrophy, induced by a partial ligation of the urethra, was used to study the accompanying changes of microvascular smooth muscle mechanics, pharmacology and morphology. A segment of a microarterial vessel to the bladder was taken from a defined anatomical location and studied in a wire myograph in vitro at the length for maximal isometric force development (Lmax). After 10 days of ligation, bladder hypertrophy resulted in a microvascular growth response compared to non-operated controls which was characterized by (i) an increase of the calculated diameter at Lmax from 134 +/- 5 microns to 222 +/- 19 microns; (ii) an increase of the media thickness from 22.4 +/- 1.9 microns to 32.2 +2- 3.0 microns; (iii) an increase of the... (More)
Rat bladder hypertrophy, induced by a partial ligation of the urethra, was used to study the accompanying changes of microvascular smooth muscle mechanics, pharmacology and morphology. A segment of a microarterial vessel to the bladder was taken from a defined anatomical location and studied in a wire myograph in vitro at the length for maximal isometric force development (Lmax). After 10 days of ligation, bladder hypertrophy resulted in a microvascular growth response compared to non-operated controls which was characterized by (i) an increase of the calculated diameter at Lmax from 134 +/- 5 microns to 222 +/- 19 microns; (ii) an increase of the media thickness from 22.4 +/- 1.9 microns to 32.2 +2- 3.0 microns; (iii) an increase of the active tension from 1.42 +/- 0.28 mN/mm to 3.06 +/- 0.33 mN/mm; (iv) no change of the wall/lumen ratio (from 0.83 +/- 0.10 to 0.79 +/- 0.15). Normalized length/force relations (active, passive and total) did not differ significantly between microarteries from control and hypertrophic bladders. Microvascular smooth muscle growth was also associated with a decreased sensitivity to K(+)-induced depolarization and an increased sensitivity to alpha 1-adrenergic stimulation. No differences were noted regarding the Ca2+ sensitivity of force during K(+)-induced depolarization. The results suggest that microvascular growth (1) is immediately and positively influenced by the organ growth; (2) results in a functional resetting of the microvascular segments towards larger diameters without gross morphological or mechanical alterations; and (3) is accompanied by pharmacological alterations of the smooth muscle reactivity. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Phenylephrine, K+ Sensitivity, Ca2+ Sensitivity, Length/force relation, Smooth muscle
in
Pflügers Archiv
volume
426
issue
6
pages
506 - 515
publisher
Springer
external identifiers
  • pmid:8052520
  • scopus:0028344779
ISSN
0031-6768
DOI
10.1007/BF00378528
language
English
LU publication?
yes
id
9212ff01-fed8-4a63-81e2-86e8b5d1eddd (old id 1108523)
date added to LUP
2008-07-24 11:42:22
date last changed
2017-02-22 11:44:33
@article{9212ff01-fed8-4a63-81e2-86e8b5d1eddd,
  abstract     = {Rat bladder hypertrophy, induced by a partial ligation of the urethra, was used to study the accompanying changes of microvascular smooth muscle mechanics, pharmacology and morphology. A segment of a microarterial vessel to the bladder was taken from a defined anatomical location and studied in a wire myograph in vitro at the length for maximal isometric force development (Lmax). After 10 days of ligation, bladder hypertrophy resulted in a microvascular growth response compared to non-operated controls which was characterized by (i) an increase of the calculated diameter at Lmax from 134 +/- 5 microns to 222 +/- 19 microns; (ii) an increase of the media thickness from 22.4 +/- 1.9 microns to 32.2 +2- 3.0 microns; (iii) an increase of the active tension from 1.42 +/- 0.28 mN/mm to 3.06 +/- 0.33 mN/mm; (iv) no change of the wall/lumen ratio (from 0.83 +/- 0.10 to 0.79 +/- 0.15). Normalized length/force relations (active, passive and total) did not differ significantly between microarteries from control and hypertrophic bladders. Microvascular smooth muscle growth was also associated with a decreased sensitivity to K(+)-induced depolarization and an increased sensitivity to alpha 1-adrenergic stimulation. No differences were noted regarding the Ca2+ sensitivity of force during K(+)-induced depolarization. The results suggest that microvascular growth (1) is immediately and positively influenced by the organ growth; (2) results in a functional resetting of the microvascular segments towards larger diameters without gross morphological or mechanical alterations; and (3) is accompanied by pharmacological alterations of the smooth muscle reactivity.},
  author       = {Boels, P J and Arner, Anders and Malmqvist, Ulf and Uvelius, Bengt},
  issn         = {0031-6768},
  keyword      = {Phenylephrine,K+ Sensitivity,Ca2+ Sensitivity,Length/force relation,Smooth muscle},
  language     = {eng},
  number       = {6},
  pages        = {506--515},
  publisher    = {Springer},
  series       = {Pflügers Archiv},
  title        = {Structure and mechanics of growing arterial microvessels from hypertrophied urinary bladder in the rat},
  url          = {http://dx.doi.org/10.1007/BF00378528},
  volume       = {426},
  year         = {1994},
}