ISSN:
1434-0879
Keywords:
Key words Force
;
velocity relation
;
Rabbit
;
Urethra
;
Lactate dehydrogenase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The aim of the study was to investigate whether the functional difference between circular and longitudinal muscles in the female rabbit urethra is reflected in their shortening properties and lactate dehydrogenase (LDH) activity. For mechanical experiments the preparations were chemically skinned to avoid influence of membrane-related mechanisms and to enable maximal activation. Force–velocity relations and the maximal shortening velocity (vmax) were determined using the isotonic quick-release method. The vmax was three times higher in longitudinal muscle. LDH isoform pattern was determined on agarose gels. The M-subunit, favourable for lactate formation, constituted 70% of the total in both types of muscle. There was no difference in the LDH isoform pattern despite the marked difference in vmax. We conclude that the difference in vmax reflects differences in the contractile machinery itself. These mechanical characteristics are advantageous for the role of the circular as a tonic muscle contracting during bladder filling, and the longitudinal as a phasic muscle active in opening up the urethra during micturition.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002400050080
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