# CALCIUM & CONTRACTILE ACTIVATION IN STRIATED MUSCLE

> **NIH NIH R01** · AUGUSTA UNIVERSITY · 1989 · $152,540

## Abstract

The aim of the proposed work is to investigate the process of
chemomechanical transduction by the contractile apparatus of striated
muscle.  The economy of transduction (i.e. "tension-cost", the ratio of
ATPase/force) will be studied by simultaneously measuring isometric force
and ATP hydrolysis in chemically skinned fibers from both fast- and slow-
twitch skeletal muscle.  ATPase will be estimated with a linked enzyme
assay using a specially-designed microfluorometer.  In addition, the
maximal velocity of unloaded shortening (Vmax), stiffness, and the rate of
redevelopment of force after a brief period of lightly-loaded isotonic
shortening will be measured.  In specific, the aim is to investigate
whether the tension-cost varies with the level of activating Ca2+.
Comparison of tension-cost of fasts-twitch and slow-twitch fibers will
indicate likely differences between fiber types.  The role of troponin C
(TnC) and myosin phosphorylatable light chains (P-LC) in any fiber-type
differences will be studied by exchange of TnC or P-LCs.  The effect of
phosphorylation of P-LCs will also be studied.  Fiber-type and TnC or P-LC
status will be verified using ultrasensitive polyacrylamide gel
electrophoresis of single fibers.  In addition to Ca2+, we will focus
primarily on the effects of changes in pH, inorganic phosphate (Pi), and
ADP because these variations are known to have significant effects on
important steps of the cross-bridge cycle.  Moreover, they are thought to
play major roles in the decline of contractile force and Vmax observed with
fatigue of intact muscle.  In this regard, pH and Pi are especially
important; therefore their interacting effects on the contractile apparatus
will be examined using chemical analogs of Pi which we will synthesize.  In
conjunction with isometric force and ATPase, the other mechanical measures
of cross-bridge number and behavior will provide detailed insight into the
mechanisms by which fatigue or hypoxia adversely affect the contractile
process.

## Key facts

- **NIH application ID:** 3156064
- **Project number:** 2R01AR031636-07A1
- **Recipient organization:** AUGUSTA UNIVERSITY
- **SAM.gov UEI:** N4WWJC8T2593
- **Principal Investigator:** Robert E GODT
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1989
- **Award amount:** $152,540
- **Award type:** 2
- **Project period:** 1982-01-01 → 1993-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3156064

## Citation

> US National Institutes of Health, RePORTER application 3156064, CALCIUM & CONTRACTILE ACTIVATION IN STRIATED MUSCLE (2R01AR031636-07A1). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3156064. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*