Locus ceruleus, noradrenergic neurons

The locus ceruleus is a structure located on the floor of the fourth ventricle in the rostral pons. It contains more than 50% of all noradrenergic neurons in the brain, and projects to almost all areas of the central nervous system. 

Six groups of cell bodies of noradrenergic neurons are clustered in the medulla oblongata, pons and midbrain. They are considered part of the reticular formation and extend from the spinal cord to the lateral pontine reticular formation. One of the best-studied of these groups is the locus ceruleus (Fig. 12-5), which has many ascending and descending projections from the pons. 

The noradrenergic neurons of the locus ceruleus have provided a useful model system for the study of opiate addiction (see Ch. 56). Acutely, opiates inhibit these neurons, in part by inhibiting the cAMP pathway via inhibition of adenylyl cyclase. Chronically, these neurons become tolerant to opiates that is, their firing rates recover toward normal levels with continued exposure to the... 

Serotonergic neurons of the raphe nuclei and noradrenergic cells of the locus ceruleus are lost... 

Most central noradrenergic neurons are located in the nucleus locus ceruleus of the pons and in neurons of the reticular formation. Fibers from these nuclei innervate a large number of cortical, subcortical, and spino-medullary fields. Many functions have been ascribed to the central noradrenergic neurons, including a role in... 

About half of all noradrenergic neurons, i.e., 12,000 on each side of the brain stem, are located in the locus ceruleus (LC). They provide the extensive noradrenergic innervation of cortex, hippocampus, thalamus, cerebellum, and spinal chord. The remaining neurons are distributed in the tegmental region. They innervate predominantly the hypothalamus, basal forebrain, and spinal chord. 

By activating presynaptic autoreceptors in brain stem locus ceruleus neurons (where most noradrenergic fibers have their origin), clonidine reduces norepine-pherine release and turnover. This inhibitory effect on noradrenergic locus ceruleus neurons, as well as direct effects on thalamic receptors, are most likely responsible for the sedative effects of clonidine (Berridge and Foote, 1991 Buzsaki et ah, 1991). 

The majority of noradrenergic neurons in the brain are located in the locus ceruleus (LC), and electrical stimulation of this region in an-... 

Bouna S, Gysling K, Galas A, Araneda S. 1994. Some noradrenergic neurons of locus ceruleus-olfactory pathways contain neuropeptide-Y. Brain Res Bull 34 413-417. 

Clonidine has beeu reported to ameliorate motor or vocal tics in roughly 50% of children so treated. It may act by reducing activity in noradrenergic neurons arising in the locus ceruleus. 

Aston-Jones G, Akaoka H, Charlety P et al. Serotonin selectively attenuates glutamate-evoked activation of noradrenergic locus ceruleus neurons. J Neurosci 1991 11 760-769. 

Postsynaptic noradrenergic neurons originating from the locus ceruleus... 

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