Comparison of tyrosine hydroxylase immunoreactivity in cochleas of chinchilla and guinea pig.
OBJECTIVE
To investigate the distribution of the tyrosine hydroxylase (TH) immunoreactivity in the cochleas of chinchilla and compare it with guinea pig.


METHODS
Ten healthy chinchillas and six healthy guinea pigs were used in this study. The surface preparation of cochleas were obtained by microdissection. The TH-like immunoreactivity on the surface preparation as examined by the avidin and biotinylated horseradish peroxidase macromolecular complex (ABC) technique and investigated with light microscopy.


RESULTS
TH-like immunoreactivity was seen in the region from modiolus to the habenula perforata. There are two different groups of fibers in this area, one is blood vessel dependent, the other is a blood vessel independent system. No TH-like immunoreactivity was present in the inner spiral bundle (ISB) and the tunnel spiral bundle (TSB) regions in chinchilla cochleas. TH-like immunoreactivity was found in the region from modiolus to the habenula perforata and the ISB and TSB regions in the organ of corti (OC) in guinea pig cochleas.


CONCLUSIONS
The presence of TH-immunoreactivity on the cochlea of chinchilla and guinea pig is different. TH-like immunoreactivity on chinchilla cochlea was involved only in the fibers corresponding to the sympathetic fibers on cochlea of guinea pig. No fibers corresponding to the dopaminergic olivocochlear lateral efferent system of guinea pig were found in ISB and TSB within the OC in chinchilla.
Liu
S
S
Department of Otolaryngology, First Hospital of Beijing Medical University, China.
D000320:Adrenergic Fibers / Q000201:enzymology; D000818:Animals; D002682:Chinchilla; D003051:Cochlea / Q000201:enzymology* / Q000294:innervation; D005260:Female; D006168:Guinea Pigs; D019262:Habenula / Q000201:enzymology; D008297:Male; D051381:Rats; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
D014446:Tyrosine 3-Monooxygenase