Journal of Neuroscience, Vol 8, 4551-4564, Copyright © 1988 by Society for Neuroscience
Colocalization of taurine- and cysteine sulfinic acid decarboxylase- like immunoreactivity in the cerebellum of the rat with monoclonal antibodies against taurine
KR Magnusson, JE Madl, JR Clements, JY Wu, AA Larson and AJ Beitz
Department of Veterinary Biology, College of Veterinary Medicine, University of Minnesota, St. Paul 55108.
Two monoclonal antibodies against fixative-modified taurine, Tau1 and Tau2,
were produced, characterized, and used in the present study to analyze the
distribution of taurine in the cerebellum of the rat. In addition,
immunohistochemical colocalization experiments were performed to determine
whether cerebellar neurons contain both taurine and its synthesizing
enzyme, cysteine sulfinic acid decarboxylase (CSADC). In ELISAs, both Tau1
and Tau2 displayed high affinities for taurine conjugated to various
carrier proteins and possessed some cross- reactivity for other amino acids
which are present in lower concentrations in the brain than taurine. Tau2
was found to recognize only taurine and hypotaurine when paraformaldehyde
was used to fix the amino acids to carrier proteins. With the use of
glutaraldehyde fixation, Tau1 cross-reacted with conjugates of beta-alanine
and hypotaurine and Tau2 cross-reacted strongly with conjugates of cysteic
acid and hypotaurine and weakly with cysteine sulfinic acid. Despite
different cross-reactivities, Tau1 and Tau2 exhibited almost identical
patterns of neuronal staining in bands of Purkinje cells in the cerebellum.
Staining of Purkinje cell dendrites was more prominent than staining of the
soma. Light immunoreactivity was present in Golgi, stellate, and basket
cells. A scattered population of granule cells displayed taurine-like
immunoreactivity at the electron microscopic level. Immunostaining was
identified in some terminals in the Purkinje cell layer and in a limited
number of mossy fibers. Tau2-like immunoreactivity was colocalized with
CSADC-like immunoreactivity in the cerebellar neurons described above.
These immunoreactive cells may represent a subpopulation of neurons that
contain a higher concentration of taurine than neighboring cells due to
their ability to synthesize taurine. The intense immunoreactive staining of
Purkinje cell dendrites provides support for the hypothesis that calcium-
dependent release of taurine in the cerebellum may originate primarily from
dendritic rather than synaptic processes and suggests a neuromodulator role
for taurine in the cerebellum.