Brainstem projections to the ventromedial medulla in cat: retrograde transport horseradish peroxidase and immunohistochemical studies.

TitleBrainstem projections to the ventromedial medulla in cat: retrograde transport horseradish peroxidase and immunohistochemical studies.
Publication TypeJournal Article
Year of Publication1999
AuthorsLai YY, Clements JR, Wu XY, Shalita T, Wu JP, Kuo JS, Siegel JM
JournalJ Comp Neurol
Date Published1999 Jun 07
KeywordsAnimals, Biological Transport, Brain Mapping, Cats, Choline O-Acetyltransferase, Female, Immunohistochemistry, Medulla Oblongata, NADPH Dehydrogenase, Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate

Stimulation of the nucleus magnocellularis (NMC) of the medulla produces changes in locomotion, muscle tone, heart rate, and blood pressure. Glutamatergic input has been found to modulate muscle tone, whereas cholinergic input has been found to mediate cardiovascular changes produced by stimulation of the NMC. The current study was designed to identify the brainstem afferents to NMC by using retrograde transport of wheat germ agglutinin and horseradish peroxidase (WGA-HRP) combined with glutamate and choline acetyltransferase (ChAT) immunohistochemical and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemical techniques. Fifty nanoliters of 2.5% WGA-HRP were microinjected into the NMC in the cat. A heavy density of WGA-HRP-labeled neurons was found in the ipsilateral mesencephalic reticular formation (MRF), periaqueductal gray, Kolliker-Fuse nucleus, and pontis centralis caudalis (PoC), in the contralateral pontis centralis oralis (PoO), and bilaterally in the nucleus paragigantocellularis lateralis. A moderate density of retrogradely labeled neurons was found in the ipsilateral side of the nuclei parvocellularis, retrorubral (RRN), PoO, and vestibular complex, in the contralateral PoC and nucleus gigantocellularis, and bilaterally in the inferior vestibular nucleus. Retrograde HRP/glutamate-positive cells could be found throughout the brainstem, with a high percentage in RRN, PoO, PoC, and MRF. Double-labeled WGA-HRP/ChAT neurons were found in the pedunculopontine nucleus. Double-labeled WGA-HRP/NADPH-d-positive neurons could be seen in many nuclei of the brainstem, although the number of labeled neurons was small. The dense glutamatergic projections to the NMC support the hypothesis that rostral brainstem glutamatergic mechanisms regulate muscle activity and locomotor coordination via the NMC, whereas the pontine cholinergic projections to the NMC participate in cardiovascular regulation.

Alternate JournalJ Comp Neurol
PubMed ID10340515
Grant ListHL41370 / HL / NHLBI NIH HHS / United States
NS14610 / NS / NINDS NIH HHS / United States