The monoamine‐containing neurons in avian brain: I. A study of the brain stem of the chicken (Gallus domesticus) by means of fluorescence and acetylcholinesterase histochemistry

Abstract

The distribution of monoamine (MA)-containing nerve cell bodies in the brain stem of the chicken (Gallus domesticus) was studied by means of paraformaldehyde and glyoxylic acid fluorescent histochemical methods. The MA neurons were further characterized morphologically and histochemically in material prepared for the demonstration of acetylcholinesterase (AChE). In the rostral midbrain of the chicken, two large collections of catecholamine (CA)-containing cells are found: one located in the ventromedial and the other in the dorsolateral (pedunculopontine nucleus) portions of the tegmentum. On the basis of their topographic location, CA content, and fiber connections, these ventromedial and dorsolateral cell groups can be tentatively associated with the CA-containing neuronal populations of the mammalian ventral tegmental area and pars compacta of the substantia nigra, respectively. In the caudal midbrain of the chicken, numerous CA-containing cells are intermingled with serotonin (5HT)-containing perikarya beneath as well as within the decussation of the superior cerebellar peduncles. At isthmus levels, abundant, closely-packed CA-containing cells are encountered along the lateral border of the central gray. These neurons, which display a very high AChE activity, appear to be equivalent to those of the mammalian locus coeruleus. A multitude of medium-sized 5HT-containing neuronal somata occurs within the raphe region of the isthmus. Some of these somata closely surround the medial longitudinal fasciculus. This 5HT-containing cell group also massively invades the lateral tegmentum, where it becomes closely intermingled with the CA-containing neurons of the locus coeruleus and subcoeruleus. All of these 5 HT-containing neurons display a moderate to high AChE activity. In the medulla the number of MA-containing neurons is much smaller than in the upper brain stem. Nevertheless, 5HT-containing cells are present within the raphe region, particularly in the upper two-thirds of the medulla, and CA-containing perikarya can be found along the lateral border of the medulla and within the confines of the nucleus solitarius. The findings of the present study reveal that the MA-containing neuronal systems in the avian brain stem are organized according to a pattern that is much more complex than the one disclosed in reptiles or in other nonmammalian vertebrates. This complexity arises in large part from the fact that the 5HT-containing systems undergo a prominent lateralization in birds, which leads to a close intermingling of 5HT-containing and CA-containing neuronal elements at various levels of the neuraxis.

A comparison of ventral tegmental neurons projecting to optic flow regions of the inferior olive vs. the hippocampal formation

“…Our localization of TH-immunoreactive elements in the pigeon VTA agrees with previous avian studies (Fuxe and Ljunggren, 1965;Ikeda and Gotoh, 1971;Dube and Parent, 1981;Bailhache and Balthazart, 1993;Waldmann and Güntürkün, 1993;Moons et al, 1994;Wynne and Güntürkün, 1995;Durstewitz et al, 1999). VTA is a continuous reticular region, the bulk of which forms a column of TH-immunoreactive tissue adjacent to the third cranial nerve, medial to the nBOR and ventral to the red nucleus.…”

“…We suggest that equivalent projections from the ventral tegmental area to the hippocampal formation and inferior olive exist Ventral tegmental area (VTA; catecholaminergic group A10) is a midbrain region characterized by dense dopaminergic immunoreactivity (Lindvall and Björklund, 1983; for review see Oades and Halliday, 1987;Gasbarri et al, 1997). In birds, the VTA, (formerly known as the area ventralis of Tsai (Reiner et al, 2004)), resides medial to the nucleus of the basal optic root (nBOR) and lateral to the third cranial nerve (Fuxe and Ljunggren, 1965;Ikeda and Gotoh, 1971;Dube and Parent, 1981;Kiss and Péczely, 1987;Bailhache and Balthazart, 1993;Moons et al, 1994;Wynne and Güntürkün, 1995;Durstewitz et al, 1999). The VTA gives rise to a robust dopaminergic input throughout the telencephalon that has been implicated in various behaviors including cognition, reward, motivation, and motor function (for review, see Horel, 1988;Oades and Halliday, 1987;Gasbarri et al, 1997;Wise 2004).…”

Phenylethanolamine N-Methyltransferase-Immunoreactive Neurons in the Medulla oblongata of the Pigeon <i>(Columba livia)</i> Projecting to the Hypothalamic Paraventricular Nucleus

“…The ST nucleus in birds displays diverse catecholaminergic neuronal populations [Dubé and Parent, 1981;Reiner et al, 1994] immunoreactive to L-DOPA and dopamine [Moons et al, 1994], or dopamine-β hydroxylase and noradrenaline [Moons et al, 1995]; this is comparable on topological and histochemical grounds to the A1/C1 catecholamine-containing cell group of the mammalian ventrolateral medulla. Furthermore, reciprocal connections between the subtrigeminal region and the parabrachial nuclear complex [Wild et al, 1990], the NTS [Arends et al, 1988], the posterior hypothalamus and the PVN [Berk and Finkelstein, 1983;Berk, 1987;present results] were reported in the pigeon.…”

Influence of 5-HT1A agonist on the feeding behavior of Coturnix japonica (Galliformes: Aves)

“…The topographic and functional organization of the serotonergic system in birds maintained homologies with reptiles and mammals (Dubé & Parent, 1981;Parent, 1981;Parent et al, 1981;Duchala et al, 1984;Sako et al, 1986;Cozzi et al, 1991;Challet et al, 1996;Gruss & Braun, 1997). However, studies about the participation of serotonin receptors in the feeding behavior of quails (Coturnix japonica) are absent from the literature, although receptors for serotonin have been identified in bird brains (Gleeson et al, 1992;Saadoun & Cabrera, 2002).…”