Biology professor studies 'superfast' muscles in animals

Sounds produced by oscillations in the special superfast muscles of a rattlesnake's tail and toadfish's swim bladder were the focus of a recent study led by Biology Professor Lawrence Rome. Most muscle tissue, made of tiny sets of thick and thin protein filaments, contracts and releases at a relatively slow rate when compared to the superfast muscles Rome studied. On the thick filaments hook-like devices, called crossbridges, attach themselves to thin filaments. Force is generated when calcium ions bind themselves to a protein called troponin which is located on the small filaments. Calcium is then secreted from the troponin into a storage sac, the sarcoplasmic reticulum, and the crossbridges detach. This process occurs in slower locomotory muscles and superfast muscles, but at a vastly slower rate in the former. The study, published in the most recent issue of the Proceedings of the National Academy of Science, found detailed information about the operation of the unique superfast muscles of snakes and toadfish. Rome's group focused, specifically, on the way in which a rattlesnake's shaker muscle and a toadfish's swim bladder muscle is able to release and reabsorb calcium rapidly to create specific sounds for various functions such as defense and mating. This rapid process allows for elevated muscle movement that is only present in these superfast muscles. Rome and his colleagues discovered that the muscles of the two species evolved independently into a form that can fill and release the sarcoplasmic reticulum quickly while their crossbridges attach and detach at an equally dizzying pace. The two processes together allow the swift oscillations required to make to a specific sound whereas a slower muscle would remain flexed and block the quick shivering needed. The result of the two functions is a vibration frequency of about 200 hertz in the toadfish and 90 hertz in a rattlesnake. According to a release by News and Public Affairs, Rome believes that the toadfish has the fastest crossbridge detachment rates and calcium transients of all vertebrates. According to the release, the study provides a great deal of insight into the way superfast muscles in other species work. The study may lead to a better understanding of how the muscles that control the eye movements in many animals, including humans, function, Rome said in the release. He also said it could possibly lead to new advancements in the treatments for various eye human diseases.