Numerous GABAergic Afferents to Locus Ceruleus in the Pericerulear Dendritic Zone: Possible Interneuronal Pool

Abstract

Most nuclei in the CNS are composed of principal neurons that project to other areas and interneurons that serve to integrate information among afferents. The noradrenergic brain nucleus locus ceruleus (LC) has appeared to be an exception to this general rule, because the LC is composed almost entirely of noradrenergic principal neurons. Here, we report that numerous small neurons in the peri-LC region become retrogradely labeled after focal injections of wheat germ agglutinin-apo (inactivated) horseradish peroxidase conjugated to colloidal gold, or pseudorabies virus (PRV), into the nuclear core of the rat LC. A substantial number of these neurons were routinely found within the dendritic field of the LC, in the area surrounding the compact cell-dense region classically defined as LC. Double labeling revealed that a large percentage of these cells stained for GABA. Ultrastructural analyses revealed axodendritic and axosomatic contacts between PRV-labeled afferents and LC neurons labeled with tyrosine hydroxylase immunohistochemistry. In addition, PRV-labeled neurons or axons were immunopositive for GABA in ultrastructural localizations. Analysis of the synaptology of immunopositive profiles demonstrated that these LC afferents in the peri-LC region receive several non-LC synaptic inputs. These results indicate that a population of small GABAergic neurons in the peri-LC dendritic zone may provide interneuronal integration for LC noradrenergic neurons.

Neuropathic and inflammatory pain are modulated by tuberoinfundibular peptide of 39 residues

“…Glutamate release potentiated by TIP39 may increase activation of GABA interneurons with subsequent inhibition of LC noradrenergic neurons and suppression of spinal norepinephrine release. This particular pool of GABA neurons and their innervation of LC neurons has been demonstrated by retrograde viral labeling (27). Communication of TIP39 signaling through GABA interneurons is consistent with the observed effects on pain behavior and barley lectin transfer.…”

Selective Loss of Catecholaminergic Wake–Active Neurons in a Murine Sleep Apnea Model

“…Noradrenergic locus ceruleus neurons were identified with sheep anti-dopamine ␤-hydroxylase (DBH) (PA3-925; ABR Affinity Bioreagents, Golden, CO) and mouse antityrosine hydroxylase (TH; 22941; Immunostar, Hudson, WI). Anti-DBH was used to demarcate noradrenergic and dopaminergic mesopontine wake-active cell groups in mice, whereas anti-TH was used for double labeling studies (below) for its robust labeling of noradrenergic and dopaminergic axons and dendrites (Aston-Jones et al, 2004). Serotonergic neurons in the dorsal raphe nucleus were localized with a mouse monoclonal anti-5-hydroxytryptamine antibody (5-HT) (20079; Immunostar, Hudson, WI).…”

Eif-2a Protects Brainstem Motoneurons in a Murine Model of Sleep Apnea

“…Sections were treated with 1% NaBH 4 in PBS and rinsed in PBS (Wang et al, 2004), before a Tris-buffered saline rinse and incubation in bovine serum albumin to minimize nonspecific labeling. To assess nuclear translocation of CHOP/GADD153, ChAT primary antibody (Table 1) labeled using biotin-SP-conjugated donkey anti-goat secondary (Jackson ImmunoResearch, West Grove, PA) was detected with DAB, whereas CHOP/GADD153 was labeled using goat antirabbit IgG conjugated to 1 nm gold particles (1:50; Amersham Biosciences, Arlington Heights, IL) as described by Aston-Jones et al (2004). For characterization of ER and polysome ultrastructure, DAB intermediate densities were avoided by labeling ChAT with gold.…”