REGULATION OF VASCULAR SMOOTH MUSCLE CONTRACTION

  • Brozovich, Frank V (PI)

Project: Research project

Project Details

Description

The overall objective of this project is to elucidate the precise molecular
mechanisms responsible for force maintenance in vascular smooth muscle
(VSM). A primary event in the initiation of smooth muscle contraction is
Ca2+-calmodulin dependent phosphorylation of the 20 kd myosin light chains
(MLC). Although MLC phosphorylation has been shown to be an important
regulator of smooth muscle contraction, an increasing body of literature
has clearly demonstrated that another regulatory system for force exists,
and this second system maybe even more important for force maintenance.
The purpose of this proposed research project is to test the hypothesis
that protein kinase C (PKC) nad caldesmon (CDM) are directly involved in
this second regulatory system for force. In order to test this hypothesis,
the specific aims are: 1) To determine the calcium sensitivity of force
produced by activation of PKC; 2) To determine the role of activation of
PKC for force developed during both the warming and alpha-agonists
stimulated contractions; 3) To determine the effects of inhibiting PKC
function on the calcium sensitivity of force; and 4) To determine the
effects of inhibiting CDM function on the calcium sensitivity of force. In
order to fulfill these specific aims, experiments will be performed with
single, freshly dissociated VSM cells. Using a technique I have developed
to isolate contractile single VSM cells from the aorta and attach these
cells to microtools, force can be recorded. After detergent skinning,
force is recorded both during activation (increasing [Ca2+]) and relaxation
(decreasing [Ca2+]). To test the roles of PKC and CDM in force
maintenance, force will be measured in solutions containing selective
inhibitors of PKC and CDM function. In addition to directly probe the
mechanism for pharmacomechanical coupling, force will be measured during
alpha-agonist stimulated contractions in alpha-toxin skinned single VSM
cells microinjected with inhibitors of PKC and/or CDM function. if PKC
and/or CDM are involved in the mechanism of force maintenance, one would
predict that inhibition of their function would result in relaxation at
activating [Ca2+]. Experiments measuring MLC phosphorylation produced by
activation of PKC and/or CDM. The information gained from this proposal
will provide direct evidence for the role(s) of PKC and/or CDM in the
regulation of force in smooth muscle contraction.
StatusFinished
Effective start/end date7/1/9011/30/06

Funding

  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health: $35,141.00
  • National Institutes of Health: $321,155.00
  • National Institutes of Health: $308,866.00
  • National Institutes of Health: $116,874.00
  • National Institutes of Health: $294,836.00
  • National Institutes of Health: $315,615.00
  • National Institutes of Health: $344,250.00
  • National Institutes of Health
  • National Institutes of Health: $344,250.00
  • National Institutes of Health: $62,496.00
  • National Institutes of Health: $119,540.00
  • National Institutes of Health: $309,109.00
  • National Institutes of Health
  • National Institutes of Health: $344,250.00

ASJC

  • Medicine(all)

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