Distribution of neurons containing phenylethanolamine N‐methyltransferase in medulla and hypothalamus of rat

Abstract

Neurons immunocytochemically labeled with the adrenaline-synthesizing enzyme phenylethanolamine N-methyltransferase were mapped in the brain of rat pretreated with colchicine. In medulla, immunoreactive cells in the C1 and C2 groups were distributed in a more complex manner than described previously. C1 neurons were identified in the reticular formation of ventrolateral medulla and were organized into two populations: (1) a cell column extending throughout the ventrolateral medulla, and lying ventral to the ambiguus cell group and either dorsal to the precerebellar lateral reticular nucleus or interposed between its two subdivisions; (2) a rostral cell cluster forming medial to the column at caudal levels and enlarging close to and in parallel with the ventral surface of the rostral ventrolateral medulla. A large proportion of cells and processes of the rostral cell group were oriented medially and ventromedially. processes of C1 neurons were traced dorsally toward the nucleus tractus solitarii, dorsal motor nucleus, and principal tegmental adrenergic bundle, ventrally toward the ventral surface, laterally toward the trigeminal complex, and medially or ventromedially toward the raphe. C2 neurons were located in the dorsomedial medulla and were subdivided into four distinct populations: (1) neurons in the rostral nucleus paragigantocellularis pars dorsalis (NGCd) and medial longitudinal fasciculus (MLF) were contiguous and similar in size and shape, with their long diameters oriented horizontally or diagonally along several axes; (2) neurons of the periventricular gray were located in a cytoarchitecturally undefined area dorsal to the MLF; these cells were ovoid, smaller, and organized more compactly than those in the NGCd-MLF; (3) a cell group in the rostromedial nucleus tractus solitarii (NTS) and dorsal motor nucleus overflowed caudally into the intermediate thirds of both structures; and (4) a parvicellular group in the NTS was compactly organized in the dorsolateral NTS and was best developed at the level of the area postrema. Processes of C2 neurons were generally directed sagitally, medially, and laterally along the ventricular floor and ventrally or medially toward the raphe; other fibers arborized and terminated within the NTS and dorsal motor nucleus. In the medulla, local processes were traced from C1 and C2 neurons directly into respective ventral and dorsal parts of the medullary raphe and surrounding intraparenchymal blood vessels. Fibers from these neurons were also followed, respectively, onto the ventral subpial surface and the floor of the fourth ventricle.(ABSTRACT TRUNCATED AT 400 WORDS)

Cell-type-specific expression of catecholamine transporters in the rat brain

“…Our results, however, indicate that neither DAT nor NET mRNA is expressed in adrenergic neurons. Although there is controversy in the literature over the role of epinephrine as a neurotransmitter in the CNS, immunocytochemical, biochemical, and electrophysiological studies have demonstrated that these adrenergic cells send projections primarily to the hypothalamus, and appear to be involved in cardiovascular homeostasis (Hiikfelt et al, 1974(Hiikfelt et al, , 1984Swanson et al, 1978;Moore and Bloom, 1979;Ruggiero et al, 1985;Tucker et al, 1987). If epinephrine functions as a neurotransmitter in these neurons, our results suggest the presence of a separate and specific transport system that terminates adrenergic neurotransmission.…”

“…3.4,B). These regions are known to contain the Cl and C2 catecholaminergic cell groups (Hiikfelt et al, 1974(Hiikfelt et al, , 1984Swanson et al, 1978;Ruggiero et al, 1985) which lie rostra1 to, but partially overlap, the distribution of the Al and A2 noradrenergic cell groups. Although a significant number of PNMT-immunoreactive neurons were detected in the regions ofthe Cl and C2 adrenergic cell groups, and the distribution of these cells corresponded to previously published maps, in no case did NET mRNA labeling exceed background over PNMTimmunoreactive cells.…”

Transgenic zebrafish that express tyrosine hydroxylase promoter in inner retinal cells

“…In our case, TH antibodies labeled only a small portion of amacrine cells, whereas PNMT antibodies labeled one to two layers of cell bodies in the proximal INL and GCL. It has been suggested that epinephrine may be synthesized from octopamine and synephrine by means of different pathways (Foster et al, 1985;Ruggiero et al, 1985).…”

Repeated 2-deoxy-D-glucose-induced glucoprivation attenuates Fos expression and glucoregulatory responses during subsequent glucoprivation.

“…Quantification of Fos-positive nuclei and cell bodies immunoreactive for both cytoplasmic TH and nuclear Fos was performed bilaterally in two sections from each animal. Catecholamine cell groups were identified from published descriptions (12)(13)(14)(15) and designated using the conventional terminology (14). C1 through C3 designate epinephrine cell groups containing both TH-ir and phenethanolamine-N-methyl-transferase (PNMT)-ir.…”