TY - CHAP
T1 - Afferent regulation of locus coeruleus neurons
T2 - Anatomy, physiology and pharmacology
AU - Aston-Jones, G.
AU - Shipley, M. T.
AU - Chouvet, G.
AU - Ennis, M.
AU - van Bockstaele, E.
AU - Pieribone, V.
AU - Shiekhattar, R.
AU - Akaoka, H.
AU - Drolet, G.
AU - Astier, B.
AU - Charléty, P.
AU - Valentino, R. J.
AU - Williams, J. T.
N1 - Funding Information: This work was supported by PHS grants NS24698, NS20463, HL08097, DA06214, MH40008, MH42796, ONR contract N00014-86-0493, AFOSR grant 90-0147, the Phillippe Foundation, the Simone et Cino del Duca Foundation, INSERM, the Fonds de la Recherche en Santé du Quebec.
PY - 1991/1/1
Y1 - 1991/1/1
N2 - Tract-tracing and electrophysiology studies have revealed that major inputs to the nucleus locus coeruleus (LC) are found in two structures, the nucleus paragigantocellularis (PGi) and the perifascicular area of the nucleus prepositus hypoglossi (PrH), both located in the rostral medulla. Minor afferents to LC were found in the dorsal cap of the paraventricular hypothalamus and spinal lamina X. Recent studies have also revealed limited inputs from two areas nearby the LC, the caudal midbrain periaqueductal gray (PAG) and the ventromedial pericoerulear region. The pericoeruleus may provide a local circuit interface to LC neurons. Recent electron microscopic analyses have revealed that LC dendrites extend preferentially into the rostromedial and caudal juxtaependymal pericoerulear regions. These extracoerulear LC dendrites may receive afferents in addition to those projecting to LC proper. However, single-pulse stimulation of inputs to such dendritic regions reveals little or no effect on LC neurons. Double-labeling studies have revealed that a variety of neurotransmitters impinging on LC neurons originate in its two major afferents, PGi and PrH. The LC is innervated by PGi neurons that stain for markers of adrenalin, enkephalin or corticotropin-releasing factor. Within PrH, large proportions of LC-projecting neurons stained for GABA or met-enkephalin. Finally, in contrast to previous conclusions, the dorsal raphe does not provide the robust 5-HT innervation found in the LC. We conclude that 5-HT inputs may derive from local 5-HT neurons in the pericoerulear area. Neuropharmacology experiments revealed that the PGi provides a potent excitatory amino acid (EAA) input to the LC, acting primarily at non-NMDA receptors in the LC. Other studies indicated that this pathway mediates certain sensory responses of LC neurons. NMDA-mediated sensory responses were also revealed during local infusion of magnesium-free solutions. Finally, adrenergic inhibition of LC from PGi could also be detected in nearly every LC neuron tested when the EAA-mediated excitation is first eliminated. In contrast to PGi, the PrH potently and consistently inhibited LC neurons via a GABAergic projection acting at GABAA receptors within LC. Such PrH stimulation also potently attenuated LC sensory responses. Finally, afferents to PGi areas that also contain LC-projecting neurons were identified. Major inputs were primarily autonomic in nature, and included the caudal medullary reticular formation, the parabrachial and Kölliker-Fuse nuclei, the PAG, NTS and certain hypothalamic areas. These results are interpreted to indicate that the LC may function in parallel to peripheral autonomic systems, providing a cognitive complement to sympathetic function.
AB - Tract-tracing and electrophysiology studies have revealed that major inputs to the nucleus locus coeruleus (LC) are found in two structures, the nucleus paragigantocellularis (PGi) and the perifascicular area of the nucleus prepositus hypoglossi (PrH), both located in the rostral medulla. Minor afferents to LC were found in the dorsal cap of the paraventricular hypothalamus and spinal lamina X. Recent studies have also revealed limited inputs from two areas nearby the LC, the caudal midbrain periaqueductal gray (PAG) and the ventromedial pericoerulear region. The pericoeruleus may provide a local circuit interface to LC neurons. Recent electron microscopic analyses have revealed that LC dendrites extend preferentially into the rostromedial and caudal juxtaependymal pericoerulear regions. These extracoerulear LC dendrites may receive afferents in addition to those projecting to LC proper. However, single-pulse stimulation of inputs to such dendritic regions reveals little or no effect on LC neurons. Double-labeling studies have revealed that a variety of neurotransmitters impinging on LC neurons originate in its two major afferents, PGi and PrH. The LC is innervated by PGi neurons that stain for markers of adrenalin, enkephalin or corticotropin-releasing factor. Within PrH, large proportions of LC-projecting neurons stained for GABA or met-enkephalin. Finally, in contrast to previous conclusions, the dorsal raphe does not provide the robust 5-HT innervation found in the LC. We conclude that 5-HT inputs may derive from local 5-HT neurons in the pericoerulear area. Neuropharmacology experiments revealed that the PGi provides a potent excitatory amino acid (EAA) input to the LC, acting primarily at non-NMDA receptors in the LC. Other studies indicated that this pathway mediates certain sensory responses of LC neurons. NMDA-mediated sensory responses were also revealed during local infusion of magnesium-free solutions. Finally, adrenergic inhibition of LC from PGi could also be detected in nearly every LC neuron tested when the EAA-mediated excitation is first eliminated. In contrast to PGi, the PrH potently and consistently inhibited LC neurons via a GABAergic projection acting at GABAA receptors within LC. Such PrH stimulation also potently attenuated LC sensory responses. Finally, afferents to PGi areas that also contain LC-projecting neurons were identified. Major inputs were primarily autonomic in nature, and included the caudal medullary reticular formation, the parabrachial and Kölliker-Fuse nuclei, the PAG, NTS and certain hypothalamic areas. These results are interpreted to indicate that the LC may function in parallel to peripheral autonomic systems, providing a cognitive complement to sympathetic function.
KW - CRF
KW - enkephalin
KW - epinephrine
KW - excitatory amino acid
KW - locus coeruleus
KW - nucleus paragigantocellularis
KW - nucleus prepositus hypoglossi
UR - http://www.scopus.com/inward/record.url?scp=0025838807&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025838807&partnerID=8YFLogxK
U2 - 10.1016/S0079-6123(08)63799-1
DO - 10.1016/S0079-6123(08)63799-1
M3 - Chapter
C2 - 1687622
T3 - Progress in Brain Research
SP - 47
EP - 75
BT - Progress in Brain Research
ER -