Premium
Hindlimb unweighting induces changes in the rat abdominal aorta RhoA‐Rho kinase pathway
Author(s) -
Summers Scott M.,
Nguyen Steven V.,
Purdy Ralph E.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.752.14
Subject(s) - phenylephrine , rhoa , rho associated protein kinase , myosin light chain kinase , myosin light chain phosphatase , abdominal aorta , myosin , endocrinology , medicine , chemistry , stimulation , aorta , rho kinase inhibitor , hindlimb , contraction (grammar) , anatomy , phosphorylation , signal transduction , biochemistry , blood pressure
Hindlimb unweighting (HU) treatment in rats mimics the cephalic fluid shift experienced by astronauts in microgravity. It may also serve as a model for ground based orthostatic hypotension. It has been shown previously that the abdominal aorta of the HU rat exhibits a deficit in contractile capacity in response to adrenergic agonists. Wistar rats were subjected to 20 days of HU treatment and their abdominal aortas were removed and sectioned into 3 mm rings. These rings and those from paired with age matched controls were subjected to concentration‐contractile response curves to either U46619 or phenylephrine with and without the Rho kinase inhibitor, Y27632. Alternatively, rings were snap frozen after exposure to 1 μM U46619 or 1 μM phenylephrine and Western blot analysis was performed. HU treatment decreased contractile response to U46619, a known activator of the Rho Pathway and decreased the inhibitory effect of Y27632. Western blotting revealed decreased levels of RhoA after HU treatment as well as decreased phosphorylation of both the 110 Kd myosin light chain phosphatase regulatory subunit after phenylephrine stimulation and myosin light chain after both U46619 and phenylephrine stimulation. It is concluded that the RhoA‐Rho kinase pathway is altered in the abdominal aorta of the HU rat and this may contribute to the HU‐induced decrease in contraction. Funded by NASA Grant NN04CK29G.