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Projections to the pontine nuclei from choline acetyltransferase‐like immunoreactive neurons in the brainstem of the cat
Author(s) -
Aas JanErik,
Brodal Per,
Baughman Robert W.,
StormMathisen Jon
Publication year - 1990
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.903000204
Subject(s) - tegmentum , pontine nuclei , choline acetyltransferase , biology , paramedian pontine reticular formation , anatomy , pons , neuroscience , brainstem , cholinergic neuron , reticular formation , horseradish peroxidase , cerebellum , cholinergic , nucleus , central nervous system , midbrain , enzyme , biochemistry
Abstract By use of retrograde transport of horseradish peroxidase‐wheat germ agglutinin (HRP‐WGA) in combination with monoclonal antibodies against choline acetyltransferase (ChAT), we show that putative cholinergic inputs to the feline pontine nuclei originate from cells in the dorsolateral pontine tegmentum. These cells form a loosely arranged continuum that nevertheless may be subdivided into two groups on the basis of differences in cell morphology. One group consists of double‐labeled cells in the periventricular gray substance medial to, and partly merging with, the nucleus locus coeruleus. The other group consists of double‐labeled cells surrounding the brachium conjunctivum. In two cats with tracer injections in the pontine nuclei, 81% and 84%, respectively, of the retrogradely labeled cells in the dorsolateral pontine tegmentum are ChAT‐like immunoreactive (ChAT‐LI). In the same experiments, many ChAT‐LI cells, but no retrogradely labeled cells, are seen in the basal telencephalon. The pontine nuclei contain a plexus of thin ChAT‐LI fibers with varicosities resembling en passant as well as terminal boutons. These ChAT‐LI fibers appear to branch extensively and cover all parts of the pontine nuclei. Following injections of rhodamine‐B‐isothiocyanate (RITC) in the thalamus and Fluoro‐Gold in the pontine nuclei and surrounding regions in the same animal, all retrogradely labeled cells in the dorsolateral pontine tegmentum are labeled with both tracers, whereas most cells in the paramedian pontine reticular formation are labeled either with RITC or Fluoro‐Gold. Thus it appears that all cells in the dorsolateral pontine tegmentum that project to the pontine nuclei also project to the thalamus. In analogy with findings by others in the dorsal lateral geniculate nucleus, we suggest that the putative cholinergic projections to the pontine nuclei may serve to modulate transmission of cerebellar afferent information in accordance with the behavioural state of the animal.