Effects of Senescence on Vascular Smooth Muscle in the Yellow Mud Turtle "Kinosternon flavescens" (Family "Kinosternidae")
Loading...
Authors
Lyons, Michael C.
Issue Date
1995-08
Type
Thesis
Language
en_US
Keywords
Turtles , Vascular smooth muscle , Aging , Old age
Alternative Title
Abstract
Current literature suggests that reptiles do not undergo senescence and certainly do not age in a manner similar to mammals. This study examines age-related changes in reptilian arteries to evaluate similarities to age-related changes in mammals. Arterial sections from a wild population of turtles ranging in age from 6 to 3% years were
examined histologically. Connective tissue-stained arteries showed statistically significant
deposition of connective tissue in the tunica media with advancing age, consistent with
senescent mammalian arteries. Living rings of arterial tissue from the same turtles were
stimulated with potassium chloride, phenylephrine, acetylcholine, and isoproterenol to
identify physiological responses in the vascular smooth muscle. No statistically significant
changes in response related to aging were observed. Contractions were produced by
acetylcholine, a feature typical of "Pseudemys scripta" and not of mammals. Isoproterenol
did not produce contractions suggesting "K. flavescens" lack beta-2 receptors or these
receptors do not operate similarly to mammals. The lack of decrease in arterial
responsiveness in senescent arteries suggests that turtles may possess a mechanism for
increasing myofibril strength in the presence of decreased myofibril mass and increased
connective tissue.
Description
28 leaves. Advisor: James L. Christiansen
Citation
Publisher
Drake University