COOPER, A.-S.*; MOFFET, S.; COOPER, R.L.; LaFayette High School, Lexington, KY.; Wash. State Univ., Pullman, WA.; Univ. of KY, Lexington, KY.: NERVE TERMINAL PRUNING IN CONJUNCTION WITH MUSCLE ATROPHY BY DISUSE & UNLOADING IN CRAYFISH

The anterior levator (a.l.) muscle of the crayfish is the major muscle for lifting the limb of walking legs and the cheliped (i.e. 1st leg). The chelipeds are the largest of the legs and contain a substantial amount of weight proportional to the whole animal in adults of most crustaceans that posses chelipeds for defense and social display. When an adult crayfish looses a cheliped by autotomy the a.l. muscle atrophies over time. This is likely because there is no more load on the muscle. The leg stump still moves suggesting functional innervation. Over a few weeks the muscle is drastically reduced in mass as compared to the contralateral control with a functional intact cheliped. The motor nerves must readjust in their strength of synaptic communication differentially between the two a.l. muscles. It was of interest to focus on the inhibitory motor nerve and its innervation profile on the a.l. muscles of intact and autotomized limbs to match extent of terminals on atrophied and normal muscles. The regrowth of the muscle as the limb regenerates and resumes a load on the a.l. muscle is also under investigation. The inhibitor motor axons and terminals were stained by anti-GABA immunocytochemistry and viewed on a confocal microscope. The physiological analysis is underway and will be reported on along with correlates of muscle mass and anatomical data of innervation. This research is significant in understanding how muscles and innervation is maintained during dynamic changes in muscle use for all animals. Funded by KY Young Researchers Program, Univ. KY (A.-S.C.) & NSF-IBN-0131459 (RLC).