Meeting Abstract

P3-103   -   Corn snake sarcomeres are predominantly on the descending limb of the length-tension curve Jurestovsky, DJ*; Astley, HC; The University of Akron, Akron, OH; The University of Akron, Akron, OH djj64@uakron.edu

The force-generating capacity of muscle depends upon many factors, including the actin/myosin overlap due to the relative length of the sarcomere. Consequently, the force output of a muscle may vary throughout its range of motion, and the body posture allowing maximum force generation may differ even in otherwise similar species. We hypothesize that corn snakes (P. guttatus), a constricting snake, would primarily have the resting sarcomere lengths (when the body is straight) on the descending limb of the length-tension curve, as this would allow peak muscular force when tightly bent during constriction of their prey. To test this hypothesis, we collected sarcomere length data by euthanizing corn snakes, preserving them with straight and maximally curved segments, dissecting target muscles, placing them in nitric acid to separate muscle fibers, and measuring the sarcomeres under a microscope. Currently we have dissected six muscles (iliocostalis, levator costae, longissimus dorsi, multifidus, semispinalis, and spinalis) of an adult corn snake (n = 1, mass = 335 g, SVL = 101 cm) at multiple positions along the body (anterior, middle, and posterior) which were preserved in a straight posture. These preliminary results showed variation in the placement of these muscles on the length-tension curve. Resting lengths of all muscles analyzed fell on the descending limb of the length-tension curve (2.23-2.91 μm). Further analysis of segments preserved maximally bent will determine the range of lengths across postures and future work will increase sample size of individuals as well as muscles.