Core-and-belt organisation of the mesencephalic and forebrain auditory centres in turtles: expression of calcium-binding proteins and metabolic activity.
The distribution of immunoreactivity to the calcium-binding proteins parvalbumin, calbindin and calretinin and of cytochrome oxidase activity was studied in the mesencephalic (torus semicircularis), thalamic (nucleus reuniens) and telencephalic (ventromedial part of the anterior dorsal ventricular ridge) auditory centres of two chelonian species Emys orbicularis and Testudo horsfieldi. In the torus semicircularis, the central nucleus (core) showed intense parvalbumin immunoreactivity and high cytochrome oxidase activity, whereas the laminar nucleus (belt) showed low cytochrome oxidase activity and dense calbindin/calretinin immunoreactivity. Within the central nucleus, the central and peripheral areas could be distinguished by a higher density of parvalbumin immunoreactivity and cytochrome oxidase activity in the core than in the peripheral area. In the nucleus reuniens, the dorsal and ventromedial (core) regions showed high cytochrome oxidase activity and immunoreactivity to all three calcium-binding proteins, while its ventrolateral part (belt) was weakly immunoreactive and showed lower cytochrome oxidase activity. In the telencephalic auditory centre, on the other hand, no particular region differed in either immunoreactivity or cytochrome oxidase activity. Our findings provide additional arguments in favour of the hypothesis of a core-and-belt organisation of the auditory sensory centres in non-mammalian amniotes though this organisation is less evident in higher order centres. The data are discussed in terms of the evolution of the auditory system in amniotes.
Belekhova
Margarita G
MG
Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia.
Chudinova
Tatiana V
TV
Repérant
Jacques
J
Ward
Roger
R
Jay
Bruno
B
Vesselkin
Nikolai P
NP
Kenigfest
Natalia B
NB
D000818:Animals; D001306:Auditory Pathways / Q000201:enzymology / Q000378:metabolism*; D064032:Calbindin 2; D064026:Calbindins; D003576:Electron Transport Complex IV / Q000378:metabolism; D007150:Immunohistochemistry; D008636:Mesencephalon / Q000378:metabolism*; D009474:Neurons / Q000201:enzymology / Q000378:metabolism; D010320:Parvalbumins / Q000378:metabolism; D016548:Prosencephalon / Q000201:enzymology / Q000378:metabolism; D030162:Reptilian Proteins / Q000378:metabolism*; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D013045:Species Specificity; D013687:Telencephalon / Q000201:enzymology / Q000378:metabolism*; D013788:Thalamus / Q000201:enzymology / Q000378:metabolism*; D014426:Turtles / Q000378:metabolism*
D064032:Calbindin 2; D064026:Calbindins; D010320:Parvalbumins; D030162:Reptilian Proteins; D064030:S100 Calcium Binding Protein G; D003576:Electron Transport Complex IV