Distribution of galanin‐like immunoreactive elements in the brain of the adult lamprey Lampetra fluviatilis

Abstract

Galanin is a brain-gut peptide present in the central nervous system of vertebrates and invertebrates. The distribution of galanin-like immunoreactive perikarya and fibers in the brain of the river lamprey Lampetra fluviatilis (Agnatha) has been studied immunocytochemically by using antisera against rat and porcine galanin. Galanin-like immunoreactive perikarya were seen in the telencephalon and mediobasal diencephalon. In the telencephalon, they were present in the nucleus olfactorius anterior, nucleus basalis, and especially, in the nucleus commissurae anterioris. The diencephalon contained most of the immunoreactive neurons. They were located in the nucleus commissurae praeinfundibularis, nucleus ventralis hypothalami, nucleus commissurae postinfundibularis, nucleus ventralis thalami, and nucleus dorsalis thalami pars medius. Most of the galanin-like immunoreactive infundibular neurons showed apical processes contacting the cerebrospinal fluid. Immunoreactive fibers and terminals were widely distributed throughout the neuraxis. In the telencephalon, the richest galaninergic innervation was found in the nucleus olfactorius anterior, lobus subhippocampalis, corpus striatum, and around the nucleus septi and the nucleus praeopticus. In the diencephalon, the highest density of galanin-like immunoreactive fibers was seen in the nucleus commissurae postopticae, nucleus commissurae praeinfundibularis, nucleus ventralis hypothalami, nucleus dorsalis hypothalami, and neurohypophysis. In the mesencephalon and rhombencephalon, the distribution of immunoreactive fibers was heterogeneous, being most pronounced in a region between the nucleus nervi oculomotorii and the nucleus interpeduncularis mesencephali, in the nucleus isthmi, and in the raphe region. A subependymal plexus of immunoreactive fibers was found throughout the ventricular system. The distribution of immunoreactive neurons and fibers was similar to that of teleosts but different to those of other vertebrate groups. The possible hypophysiotropic and neuroregulatory roles of galanin are discussed.

Sex difference and steroidal stimulation of galanin immunoreactivity in the ferret's dorsal preoptic area/anterior hypothalamus

“…The distribution of galanin-IR cells in the POA, AH, and hypothalamus has been previously described in adults of several species, including lamprey (Jiménez et al, 1996), sailfin molly Parsons, 1991a, 1991b), turtle (Jiménez et al, 1994), several amphibians (Olivereau and Olivereau, 1992), chicken (Józsa and Mess, 1993), and many mammals including rats (Melander et al, 1986), opposums (Elmquist et al, 1992), gerbils (Ulibarri and Rust, 1996), pigs (Pearson et al, 1996), and primates (Kordower et al, 1992) including man (Gai et al, 1990). In some instances the distribution of galanin-IR cells in the POA or hypothalamus has been shown to be sexually dimorphic.…”

Afferent and efferent connections of the parapineal organ in lampreys: A tract tracing and immunocytochemical study

“…10D,E). The possible origin of these galanin-ir fibers was not determined because none of the galanin-ir brain nuclei reported in a previous study of the river lamprey (Jiménez et al, 1996) corresponds with the efferent nuclei demonstrated by DiI application to the parapineal organ.…”

“…The other brains were cryoprotected with 30% sucrose, frozen with liquid nitrogen, sectioned (15-µmthick) in the same planes on a cryostat, and processed according to the immunoperoxidase technique. Briefly, sections were incubated with one of the primary antisera raised in rabbits against GABA (Chemicon, Temecula, CA; Affinity, Mamhead, U.K.; or Sigma; Pombal et al, 1997; dilution, 1:1,000 to 1:2,000), 5-HT (Zhang et al, 1996; dilution 1:1,000), SP ; dilution 1:2,000), CR (7696, Swant, Bellinzona, Switzerland;Schwaller et al, 1993; dilution, 1:1,000), NPY (Sigma; dilution, 1:600), or galanin (Jiménez et al, 1996; dilution 1:1,500). They were subsequently incubated with goat anti-rabbit (Dakopatts, Glostrup, Denmark; dilution, 1:60) and rabbit peroxidase-antiperoxidase complex (Dakopatts; dilution, 1:300).…”

Galanin-like immunoreactivity in the brain and pituitary of the "four-eyed" fish, Anableps anableps

“…It was first isolated and characterized from the porcine intestine (Tatemoto et al 1983). Many studies have demonstrated the distribution of GAL-like immunoreactive (ir) neurons and fibers in the brain of mammals (Skofitsch and Jacobowitz 1985;Melander et al 1986;Levin et al 1987;Palkovits et al 1987;Blasco et al 1989;Gaymann and Martin 1989;Gentleman et al 1989;Walker et al 1989;Kordower and Mufson 1990;Meister et al 1990;Elmquist et al 1992;Kordower et al 1992), birds (Józsa and Mess 1993), reptiles (Jiménez et al 1994), amphibians (Wolfbauer and Skofitsch 1989;Lázár et al 1991;Olivereau and Olivereau 1992), bony and cartilaginous fish (Batten et al 1990a(Batten et al , 1990bParsons 1991a, 1991b;Holmqvist and Ekström 1991;Olivereau 1991a, 1991b;Vallarino et al 1991;Holmqvist and Carlberg 1992;Yamamoto et al 1992;Magliulo-Cepriano et al 1993;Anglade et al 1994;Prasada Rao et al 1996;Rodríguez-Gómez et al 2000;Jadhao and Meyer 2000), and the sea lamprey (Jiménez et al 1996). Furthermore, the distribution of GAL and its receptor-binding sites in the brain and pituitary are well documented in the rat (Meister and Hökfelt 1992), sea bass (Moons et al 1991), and Atlantic salmon (Holmqvist and Carlberg 1992).…”