Journal article
Columnar Distribution of Catecholaminergic Neurons in the Ventrolateral Periaqueductal Gray (vlPAG) and Their Relationship to Efferent Pathways
Synapse (New York, N.Y.), Vol.67(2), pp.94-108
02/2013
Handle:
https://hdl.handle.net/2376/109857
PMCID: PMC3553663
PMID: 23152302
Abstract
The periaqueductal gray (PAG) is a critical brain region involved in opioid analgesia and provides efferents to descending pathways that modulate nociception. In addition, the PAG contains ascending pathways to regions involved in the regulation of reward, including the substantia nigra (SN) and the ventral tegmental area (VTA). SN and VTA contain dopaminergic neurons that are critical for the maintenance of positive reinforcement. Interestingly, the PAG is also reported to contain a population of dopaminergic neurons. In this study, the distribution of catecholaminergic neurons within the ventrolateral (vl) PAG was examined using immunocytochemical methods. In addition, the catecholaminergic PAG neurons were examined to determine whether these neurons are integrated into ascending (VTA, SN) and descending (RVM) efferent pathways from this region. The immunocytochemical analysis determined that catecholaminergic neurons in the PAG are both dopaminergic and noradrenergic and these neurons have a distinct rostrocaudal distribution within the ventrolateral column of PAG. Dopaminergic neurons were concentrated rostrally and were significantly smaller than noradrenergic neurons. Combined immunocytochemistry and tract tracing methods revealed that catecholaminergic neurons are distinct from, but closely associated with, both ascending and descending efferent projection neurons. Finally, by electron microscopy, catecholaminergic neurons showed close dendritic appositions with other neurons in PAG, suggesting a possible non-synaptic mechanism for regulation of PAG output by these neurons. In conclusion, our data indicate that there are two populations of catecholaminergic neurons in the vlPAG that form dendritic associations with both ascending and descending efferents suggesting a possible non-synaptic modulation of vlPAG neurons.
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Details
- Title
- Columnar Distribution of Catecholaminergic Neurons in the Ventrolateral Periaqueductal Gray (vlPAG) and Their Relationship to Efferent Pathways
- Creators
- Shelby K Suckow - Oregon Health & Science University, Department of Physiology and Pharmacology, Portland, OR 97223, USAEmily L Deichsel - Oregon Health & Science University, Department of Physiology and Pharmacology, Portland, OR 97223, USASusan L Ingram - Oregon Health & Science University, Department of Neurological Surgery, Portland, OR 97223, USAMichael M Morgan - Washington State University Vancouver, Department of Psychology, Vancouver, WA 98686, USASue A Aicher - Oregon Health & Science University, Department of Physiology and Pharmacology, Portland, OR 97223, USA
- Publication Details
- Synapse (New York, N.Y.), Vol.67(2), pp.94-108
- Academic Unit
- Psychology, Department of
- Grant note
- P30 NS061800 || NS / National Institute of Neurological Disorders and Stroke : NINDS R01 DA027625 || DA / National Institute on Drug Abuse : NIDA
- Identifiers
- 99900547897701842
- Language
- English
- Resource Type
- Journal article