CHOLINE-ACETYLTRANSFERASE, GLUTAMATE-DECARBOXYLASE, TYROSINE-HYDROXYLASE, CALCITONIN-GENE-RELATED PEPTIDE AND OPIOID-PEPTIDES COEXIST IN LATERAL EFFERENT NEURONS OF RAT AND GUINEA-PIG
S. Safieddine et al., CHOLINE-ACETYLTRANSFERASE, GLUTAMATE-DECARBOXYLASE, TYROSINE-HYDROXYLASE, CALCITONIN-GENE-RELATED PEPTIDE AND OPIOID-PEPTIDES COEXIST IN LATERAL EFFERENT NEURONS OF RAT AND GUINEA-PIG, European journal of neuroscience, 9(2), 1997, pp. 356-367
The lateral efferent (olivocochlear) innervation of the cochlea origin
ates in the brainstem lateral superior olive. It is likely to use acet
ylcholine, gamma-aminobutyric acid, dopamine and various neuropeptides
as neurotransmitters and/or neuromodulators. In order to determine th
e different coexistence patterns of these molecules in lateral efferen
t perikarya, we have used double and triple immunofluorescence co-loca
lization techniques to colocalize choline acetyltransferase, glutamate
decarboxylase, tyrosine hydroxylase, calcitonin gene-related peptide
and enkephalins in single sections of the lateral superior olive. We a
lso used a non-radoactive in situ hybridization technique onto serial
sections of this nucleus to confirm the immunofluorescence co-localiza
tion data at the mRNA level. Whatever the pair or triplet of primary a
ntibodies tested was, a high ratio of coexistence was observed in the
immunofluorescence experiments. In triple co-localization experiments,
90-93% of the choline acetyltransferase-like immunoreactive neurons w
ere also immunoreactive to the two other antigens investigated. The in
situ hybridization co-localization data, based on the use of biotin-l
abelled oligoprobes, qualitatively confirmed these immunofluorescence
data. In conclusion, it can be postulated that acetylcholine, gamma-am
inobutyric acid, dopamine, calcitonin gene-related peptide, enkephalin
s and dynorphins (whose coexistence with choline acetyltransferase and
enkephalins has been previously described immunocytochemically) coexi
st in lateral efferent neurons. Based on these results, it is tempting
to propose the lateral efferent innervation as a useful model with wh
ich the functional implications of the coexistence of neurotransmitter
s/neuromodulators can be investigated in vivo.