Silke KrÃger, Casey S. Butler & Reinhard Lakes-Harlan (2011): Morphological and
physiological regeneration in the auditory system of adult Mecopoda elongata
(Orthoptera: Tettigoniidae). J. Comp. Physiol. A 197 (2), 181-192.
Abstract: Orthopterans are suitable model organisms for investigations of
regeneration mechanisms in the auditory system. Regeneration has been described
in the auditory systems of locusts (Caelifera) and of crickets (Ensifera). In
this study, we comparatively investigate the neural regeneration in the
auditory system in the bush cricket Mecopoda elongata. A crushing of the
tympanal nerve in the foreleg of M. elongata results in a loss of auditory
information transfer. Physiological recordings of the tympanal nerve suggest
outgrowing fibers 5 days after crushing. An anatomical regeneration of the
fibers within the central nervous system starts 10 days after crushing. The
neuronal projection reaches the target area at day 20. Threshold values to low
frequency airborne sound remain high after crushing, indicating a lower
regeneration capability of this group of fibers. However, within the central
target area the low frequency areas are also innervated. Recordings of auditory
interneurons show that the regenerating fibers form new functional connections
starting at day 20 after crushing.
URL: http://www.springerlink.com/content/w721215082h77g03/
For reprints please contact Reinhard Lakes-Harlan (email:
Doreen MÃckel, Ernst-August Seyfarth & Manfred KÃssl (2011): Otoacoustic
emissions in bushcricket ears: general characteristics and the influence of the
neuroactive insecticide pymetrozine. J. Comp. Physiol. A 197 (2), 193-202.
Abstract: The tympanal organ of the bushcricket Mecopoda elongata emits
pronounced distortion-product otoacoustic emissions (DPOAEs). Their
characteristics are comparable to those measured in other insects, such as
locusts and moths, with the 2f1âf2 emission being the most prominent one. Yet
the site of their generation is still unclear. The spatial separation between
the sound receiving spiracle and the hearing organ in this species allows
manipulations of the sensory cells without interfering with the acoustical
measurements. We tried to interfere with the DPOAE generation by
pharmacologically influencing the tympanal organ using the insecticide
pymetrozine. The compound appears to act selectively on scolopidia, i.e., the
mechanosensor type characteristically constituting tympanal organs. Pymetrozine
solutions were applied as closely as possible to the scolopidia via a cuticle
opening in the tibia, distally to the organ. Applications of pymetrozine at
concentrations between 10â3 and 10â7 M to the tympanal organ led to a
pronounced and irreversible decrease of the DPOAE amplitudes.
URL: http://www.springerlink.com/content/a173m40732850121/
For reprints please contact D. MÃckel (email:
Kind regards
Sonja
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Dr. Sonja Amoser
SteinrieglstraÃe 286
3400 Weidlingbach
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