Date of Award

1991

Degree Type

Thesis

Degree Name

M.Sc.

Department

Biological Sciences

First Advisor

Taylor, P.,

Keywords

Biology, Animal Physiology.

Rights

CC BY-NC-ND 4.0

Abstract

The effect of staphylococcal alpha toxin on myocardial contractile function was examined in rat papillary muscles of the right ventriculum. When muscles were stretched at L$\sb{\rm max}$, 26$\sp\circ$C and in 1.0 mM extracellular Ca$\sp{2+}$, a low concentration (10 HU/mL) of purified toxin significantly altered the developed force which was stabilized within 30 minutes while the passive tension remained unchanged. The peak tension, the maximal rate of force development, and the maximal rate of relaxation were all reduced, while the timing parameters of the twitch were unaltered. Heat inactivated toxoid is neither hemolytic nor lethal, but has similar cardiac dysfunctional effects as the toxin. The developed force of the muscles was decreased with 30 minutes exposure to the toxoid, while the passive force was unchanged. The twitch characteristics after toxoid treatment were similar to these after toxin treatment. A transient increase of the developed force was linearly related to toxin concentration. The rest potentiation experiments performed after treatment of 30 minutes of higher toxin concentration (100 HU/mL) suggest that the toxin inhibited Ca$\sp{2+}$ movement from sarcolemma to sarcoplasmic reticulum. (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1991 .X853. Source: Masters Abstracts International, Volume: 31-01, page: 0234. Supervisor: P. Taylor. Thesis (M.Sc.)--University of Windsor (Canada), 1991.

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