Abstract:
Gender-related differences in various gastric
functions and diseases have been reported, with women
having a higher prevalence of gastrointestinal disturbances
than men. The aim of this study was to investigate sexdependent
differences in activation of the Rho-associated
protein kinase (ROCK; RhoA/Rho kinase) pathway and
muscle contraction in the stomach using single gastric
smooth muscle cells (GSMC) from male and female
Sprague?Dawley rats. Expression of ROCK1 and ROCK2
protein and acetylcholine (ACh)-induced activation of
RhoA and ROCK were measured using a specifically
designed enzyme-linked immunosorbent assay and activity
assay kits, respectively. Contraction of a single GSMC was
measured by scanning micrometry in the presence or
absence of the ROCK inhibitor Y27632 dihydrochloride.
ACh-induced activation of RhoA and ROCK and subsequent
contraction were greater in male rats than in female
rats but neither was related to differences in the expression
of ROCK1 or ROCK2 or total RhoA amount. Most
important, Y27632 inhibited and abolished differences in
ACh-induced contraction in both sexes. In conclusion,
increased ACh-induced contraction in the GSMC of male
rats is attributable to greater RhoA/ROCK activation
independent of differences in the expression of ROCK
isoforms or total RhoA.