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Title: ANATOMY AND INNERVATION OF THE FLEXOR TIABIALIS MUSCLE OF THE COCKROACH LEUCOPHAEA MADERAE (FABRICIUS)

Author
item Cook, Benjamin
item Pryor, Nan

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Recent research has shown that neuropeptides (short chains of amino acids) regulate many critical life processes in insects and as such they offer considerable potential for the development of new and better methods of pest insect control. In earlier studies, we discovered a peptide in the head of the cockroach that inhibits the contraction of certain muscles of that insect. This report describes for the first time a test procedure that can be used to study the effects of neuropeptides on the skeletal muscles of the cockroach. If new and better pesticides for insects are to be developed, it is critical to understand in some detail just how the natural product (neuropeptide) accomplishes its action in the living system that it effects. This new test is an important contribution toward developing new pesticides based on neuropeptide technology.

Technical Abstract: The flexor tibialis is a large muscle positioned along the posterior border of the femur of the Madeira cockroach, Leucophaea maderae (Fabricius). The large muscle consisted of 8 muscle groups or bundles that originated on a long central apodeme in the femur and inserted on the lateral cuticular faces of the femur and along the boundary between the femur and the trochanter. This muscle received innervation from branches of the 5th nerve which arose from the metathoracic ganglion. Many flexor muscle fibers attached to the central apodeme had ultrastructural features that resembled the intercalated discs of heart muscle. The myofibrils in cross-section were bound by the distinctive fenestrations of the sarcoplasmic reticulum. Although the characteristic thick and thin filaments within the myofibrils were evident, there were 11 to 12 thin filaments around each thick one instead of the 6 to 1 ratio usually found in skeletal muscle. Nerve-muscle junctions and small tracheae were detected in the intermyofibrillar spaces.