Experimental Brain Research

, Volume 73, Issue 1, pp 69–77

Projections from the ventral tegmental area and mesencephalic raphe to the dorsal raphe nucleus in the rat

Evidence for a minor dopaminergic component

Authors

  • P. Kalén
    • Department of Medical Cell ResearchUniversity of Lund
  • G. Skagerberg
    • Department of Medical Cell ResearchUniversity of Lund
  • O. Lindvall
    • Department of Medical Cell ResearchUniversity of Lund
Article

DOI: 10.1007/BF00279662

Cite this article as:
Kalén, P., Skagerberg, G. & Lindvall, O. Exp Brain Res (1988) 73: 69. doi:10.1007/BF00279662

Summary

The origins of the dopaminergic innervation of the rat dorsal raphe nucleus (NRD) have been investigated using a combination of fluorescent retrograde tracing and fluorescence histochemistry. Stereotaxic microinjections of True Blue were placed in the central, caudal and lateral portions of the NRD, and after 6–12 days survival the brains were processed for fluorescence histochemical detection of catecholamines. Retrogradely labeled neurons were searched for in the diencephalic A11 and A13 dopaminergic cell groups, substantia nigra, ventral tegmental area (VTA) and the linear, central superior and dorsal raphe nuclei. The various NRD injections consistently resulted in retrograde labeling of a small number of catecholamine-containing, presumed dopaminergic cell bodies, confined mainly to three regions: the VTA, the linear and central superior raphe nuclei and the NRD itself. The present findings indicate that not only dopaminergic neurons in the VTA but also the system of catecholamine-containing cells, extending dorsally and caudally from the VTA within the midline raphe area, project to the NRD. Although often similar in size, shape and distribution to the catecholaminergic neurons the majority of retrogradely labeled cells in these regions were, however, found to be non-catecholaminergic.

Key words

Catecholamine Dopamine Dorsal raphe nucleus Retrograde tracer Ventral tegmental area

Abbreviations

3

Principal oculomotor nucleus

4

Trochlear nucleus

Aq

Cerebral aqueduct

cp

cerebral peduncle

cst

cortico-spinal tract

dscp

decussation of the superior cerebellar peduncle

DTg

Dorsal tegmental nucleus

fr

fasciculus retroflexus

IF

Interfascicular nucleus

IP

Interpeduncular nucleus

LL

nucleus of the lateral lemniscus

ml

medial lemniscus

mlf

medial longitudinal fasciculus

mNV

mesencephalic trigeminal nucleus

NLC

Nucleus linearis caudalis

NLR

Nucleus linearis rostralis

NRD

Dorsal raphe nucleus

PAG

Periaqueductal grey

PN

Pontine nucleus

PRN

Pontine raphe nucleus

R

Red nucleus

RCS

Nucleus raphe centralis superior

SN

Substantia nigra

VTA

Ventral tegmental area

VTg

Ventral tegmental nucleus

Copyright information

© Springer-Verlag 1988