Effects of tissue extracts on oviduct contraction in the migratory grasshopper, Melanoplus sanguinipes

The isolated oviduct of the migratory grasshopper, Melanoplus sanguinipes, shows a myogenic, rhythmic pattern of contraction. The pattern of contracti on can be modified by treatment with hemolymph or extracts from a variety o f tissues from animals of differing age, sex, and mated status. Extracts of oviducts and ventral nerve cord (VNC), as well as hemolymph, from both vir gin and mated females were almost always stimulating, though their effect o n frequency, amplitude and/or tonus varied. In contrast, whereas extracts o f spermatheca and brain from mated females were stimulating, extracts of th ese tissues from virgin females inhibited contraction. All male material te sted (long hyaline tubules (LHT), the male accessory gland complex less the LHT, testes, brain, VNC and hemolymph) stimulated oviduct contraction in a dose-dependent manner, usually enhancing at least two of frequency, amplit ude and tonus. However, oviposition-stimulating protein, a purified product of the LHT, provoked only an increase in frequency when applied to the ovi duct. LHT extract modulated the effects of virgin female tissue extracts, a lways in a stimulatory manner. (C) 2000 Elsevier Science Ltd. All rights re served.