Stereotaxic Mapping of the Monoamine Pathways in the Rat Brain*

Abstract

The ascending monoamine pathways in the rat brain are demonstrated by the pile up of fluorescent material occurring in the axons after various types of lesions. The anatomy of the pathways is outlined in drawings of frontal sections of the brain and the origin and termination of several pathways is determined by studying the anterograde and retrograde degeneration occurring after well localised lesions. It is possible to separate the ascending NA pathways into a dorsal and a ventral bundle ofaxons. The dorsal bundle innervates the cortex and the hippocampus and the ventral bundle supplies NA nerve terminals to the medulla, the pons, the mesencephalon and the diencephalon, The dorsal bundle is found to originate in the locus coeruleus. Lesions of this nucleus abolish the nerve terminals in all cortical areas and in several other areas of the brain indicating a unique role for the locus coeruleus in influencing the activity of the entire brain. The 5-HT pathways have a distribution similar to the ventral NA pathyway. The course of the nigro-striatal and the mesolimbic DA pathways is presented in detail.* The following abbreviations are used: Noradrenaline (NA); dopamine (DA); 5hydroxytryptamine (5-HT); a-methyl-noradrenaline (a-m-NA); 6-hydroxydopamine (6-0H-DA).

Differential Role of Galanin Receptors in the Regulation of Depression-Like Behavior and Monoamine/Stress-Related Genes at the Cell Body Level

“…Measurements were performed on four sections for the LC (left and right independently), and on 4-6 sections for the DR and MR, and the mean value was calculated for each animal. Since there exist significant anterior-posterior differences in the expression of various genes in the DR (Day et al, 2004), the analysis was performed on sections taken at identical levels of mid-rostral DR, the area projecting to the forebrain (Ungerstedt, 1971;Azmitia and Segal, 1978;Steinbusch, 1981). The DR nucleus was subdivided into lateral (lDR), dorsal (dDR), and ventral (vDR) subnuclei, which were each assessed individually.…”

Behavioral Effects of Psychomotor Stimulant Infusions into Amygdaloid Nuclei

“…Specifically, the BlA sends dense excitatory projections to the NAc, and both the CeA and the NAc are part of the extended amygdala (Fuller et al 1987;McDonald 1996). In addition, the CeA receives dense dopamine (DA) efferents from the ventral tegmental area, and consequently, has more DA terminals relative to other amygdaloid nuclei (Ben-Ari et al 1975;Kilts and Anderson 1987;Ungerstedt 1971). The CeA also projects back to the ventral tegmental area and substantia nigra compacta, which contain the cell bodies of the mesocorticolimbic and nigrostriatal DA systems, respectively (Wallace et al 1992).…”

Adrenergic innervation of the rat hypothalamus

“…It is known that the ascending catecholaminergic fibers innervating the hypothalamus cross the midline or give off a collateral fiber to the contralateral side on their way up [10,23]. These findings were confirmed when nerve terminals in the paraventricular nucleus were found to have degenerated following surgical sagittal transection of the medulla.…”

“…They have been assumed to join the ventral noradrenergic bundle [6,23]. Adrenergic fibers which terminate in the hypothalamus probably do not follow this route, especially not in the lower part of the medulla oblongata.…”