Preoptic projections to Barringon's nucleus and the pericoerulear region: Architecture and terminal organization
Article first published online: 9 OCT 2004
Copyright © 1994 Wiley-Liss, Inc.
Journal of Comparative Neurology
Volume 347, Issue 1, pages 1–24, 1 September 1994
How to Cite
Rizvi, T. A., Ennis, M., Aston-Jones, G., Jiang, M., Liu, W.-L., Behbehani, M. M. and Shipley, M. T. (1994), Preoptic projections to Barringon's nucleus and the pericoerulear region: Architecture and terminal organization. J. Comp. Neurol., 347: 1–24. doi: 10.1002/cne.903470102
- Issue published online: 9 OCT 2004
- Article first published online: 9 OCT 2004
- Manuscript Accepted: 4 MAR 1994
- sexual dimorphism;
- lateral dorsal tegmentum;
- locus coeruleus
The medial preoptic area (MPO), a sexually dimorphic region, plays a pivotal role in neuroendocrine function and reproductive behavior. We recently reported that MPO projects heavily to the midbrain periaqueductal gray (PAG). We also noted that MPO projects to the dorsolateral pontine tegmentum. Here we identified the cells of origin of the MPOtegmental projection and delineated the terminal organization of MPO projections to Barrington's nucleus, locus coeruleus (LC), and the rostromedial pericoerulear region (pLCrm). Correlative cyto- and chemoarchitectonic studies were done to define better the nuclear groups of the dorsolateral pontine tegmentum.
Retrograde tracing revealed that MPO neurons projecting to the dorsolateral pontine tegmentum are preferentially distributed in distinct subregions of MPO, including the sexually dimorphic medial preoptic nucleus (MPN). Anterograde tracing with wheat germ agglutininhorseradish peroxidase or Phaseolus vulgaris leucoagglutinin demonstrated considerable target specificity in projections from MPO to the dorsolateral pontine tegmentum. Barrington's nucleus receives a dense focal input along its entire rostrocaudal axis. In addition, pLCrm is heavily targeted by MPO inputs; pLCrm contains a concentrated plexus of extranuclear dendrites of LC neurons. The lateral dorsal tegmental (LDT) nucleus and LC proper receive only sparse input from MPO.
MPO projections to Barrington's nucleus could regulate micturition reflexes during reproductive behavior. The MPOpLCrm projection could influence noradrenergic LC neurons in relation to reproductive and/or gonadal steroid function. Given the strong established connections from olfactory structures to MPO, it is possible that the MPOLC pathway provides an anatomical substrate for olfactory modulation of arousal. © 1994 Wiley-Liss, Inc.