Galanin-like immunoreactivity in the chicken brain

Abstract

The anatomical distribution of neurons containing galanin has been studied in the central nervous system of the chicken by means of immunocytochemistry using antisera against rat galanin. Major populations of immunostained perikarya were detected in several brain areas. The majority of galanin-immunoreactive cell bodies was present in the hypothalamus and in the caudal brainstem. Extensive groups of labeled perikarya were found in the paraventricular, periventricular, dorsomedial and tuberal hypothalamic nuclei, and in the nucleus of the solitary tract in the medulla oblongata. In the telencephalon, immunoreactive perikarya were observed in the preoptic area, in the lateral septal nucleus and in the hippocampus. The mesencephalon contained only a few galanin-positive perikarya located in the interpeduncular nucleus. Immunoreactive nerve fibers of varying density were detected in all subdivisions of the brain. Dense accumulations of galanin-positive fibers were seen in the preoptic area, periventricular region of the diencephalon, the ventral hypothalamus, the median eminence, the central gray of the brainstem, and the dorsomedial caudal medulla. The distributional pattern of galanin-immunoreactive neurons suggests a possible involvement of a galanin-like peptide in several neuroregulatory mechanisms.

Galanin immunoreactivity in the brain of the desert lizard Uromastyx acanthinura during activity season

“…The absence of galaninergic perikarya in the telencephalon of the U. acanthinura was unexpected but agrees with results obtained in the snake [18] and turtle [9] and differs from those found in amphibians [19,20], birds [16,17] and mammals [12,13,15] where the immunoreactive neurons were detected in the septum. This latter is supposed to be involved in the regulation of the water balance [52,53].…”

“…In fact, in fish, the perikarya have been identified in the preoptic and tuberal hypothalamus [8,[23][24][25]33]. In amphibians [19,20], birds [16,17] and chelonian [9], galanin-Ir neurons were found in the hypothalamus, telencephalon, mesencephalon and rombencephalon. In mammals, the galanin-Ir cell bodies were widely distributed in the CNS, particularly in the hypothalamus in the preoptic area, the infundibular/arcuate nucleus, the mediobasal hypothalamus, and periphery of the supraoptic and the paraventricular nuclei [12,13,15,34,35].…”

“…Moreover, the expression of galanin is elevated following estrogen administration, neuronal activation, denervation and/or nerve injury, as well as during development [1]. The use of immunohistochemical methods revealed a wide distribution of galanin in the brain of several vertebrate groups: mammals [12][13][14][15], birds [16,17], reptiles [9,18], amphibians [19][20][21][22] and fish [8,[23][24][25].…”

Galanin Immunoreactivity in Mouse Basal Forebrain: Sex Differences and Discrete Projections of Galanin-Containing Cells beyond the Blood-Brain Barrier

“…In the preoptic area in mice, only scattered staining for GAL-IR cells was present. GAL-IR cells in the lateral septal area in chicken [10]and in the suprachiasmatic nucleus in primates [9, 21]were not detected in mice.…”

“…Even though the overall pattern of GAL immunoreactivity (IR) in the central nervous system is similar in the various vertebrates studied so far, variations such as the presence of GAL-IR cell bodies in the suprachiasmatic nucleus in primates [9], staining for a dense cluster of GAL-positive cells in the lateral septum in chicken [10]etc. have also been reported.…”