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Innervation of the amphibian and basilar papillae in the leopard frog: Reconstructions of single labeled fibers
Author(s) -
Simmons D. D.,
Bertolotto C.,
Narins P. M.
Publication year - 1992
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.903220205
Subject(s) - leopard frog , rana , major duodenal papilla , biology , anatomy , amphibian , lingual papilla , ganglion , bullfrog , grenouille , hair cell , inner ear , neuroscience , salientia , endocrinology , taste , gene , ecology , xenopus , biochemistry
Abstract Amphibians have two auditory organs specialized for reception of airborne sounds: the amphibian papilla and the basilar papilla. In this report we examine the morphology of the ganglion cells and the afferent innervation of the sensory epithelium in both auditory organs of the leopard frog, Rana pipiens pipiens. Extracellular injections of either biocytin or horseradish peroxidase (HRP) were made into the VIII nerve; they labeled ganglion cells, their axons, and their terminal fibers within the papillae. Ganglion cells that projected to either the amphibian papilla or basilar papilla had cell bodies that were morphologically distinct from other labeled cells. In the amphibian papilla thick fibers terminated in the rostral portion and thin fibers terminated in the caudal portion. Labeled fibers in the rostral portion traveled short distances before making contacts with up to nine hair cells whereas labeled fibers in the caudal portion traveled longer distances and contacted no more than five hair cells. In the basilar papilla labeled fibers were thick (around 4 μm) and terminated on as many as nine hair cells. Consistent with studies from the bullfrog, Rana catesbeiana , our results suggest that the amphibian papilla of R. pipiens pipiens has a convergent innervation (i.e., multiple hair cells provide input to a single ganglion cell) and is topographically organized. However, in contrast to reports in other ranid species, a highly convergent innervation like that found in the amphibian papilla is also found in the basilar papilla. © 1992 Wiley‐Liss, Inc.