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Restoration of morphological and functional integrity in the regenerating eye of the giant African land snail Achatina fulica
Author(s) -
Bobkova Marina V.,
Tartakovskaya Olga S.,
Borissenko Serguei L.,
Zhukov Valery V.,
MeyerRochow Victor B.
Publication year - 2004
Publication title -
acta zoologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.414
H-Index - 37
eISSN - 1463-6395
pISSN - 0001-7272
DOI - 10.1111/j.0001-7272.2004.00152.x
Subject(s) - achatina , biology , anatomy , stimulus (psychology) , land snail , flicker fusion threshold , optic nerve , visual phototransduction , retinal , cornea , snail , retina , neuroscience , botany , flicker , psychology , ecology , electrical engineering , psychotherapist , engineering
To determine whether vision returns to its original state following eye removal in Achatina fulica , light and electron microscope examinations, electrophysiological recordings and behavioural tests were carried out on the regenerating snails. Reparative morphogenesis can result in the restoration of the peripheral sense organ even in the absence of complete regrowth of the tentacle, but it can also lead to the formation of aberrant regenerates. We found that anatomically and ultrastructurally the eyes of the ‘most normal’ regenerates were basically the same as the original eyes. Under normal conditions each eye is composed of a principal and an accessory eye, both sharing a common cornea. The only difference between regenerated and native eyes is the smaller size of the former, as a result of a reduced number of retinal cells. Electroretinographic responses revealed that the molecular mechanism of phototransduction is restored, in principle, but that flicker fusion frequency in the regenerated eye is significantly lower than in the normal eye. The directional movement to a visual stimulus (a black stripe of 45° width) had not completely recovered even 6 months after amputation. This suggests that the central projections of the optic nerve had not become fully re‐established at the time of testing.