Analysis of the ontogeny of galanin in the rat central nervous system by immunohistochemistry and radioimmunoassay

Abstract

The development of galanin-like immunoreactivity in the rat central nervous system has been investigated immunologically. Galanin-positive processes in the central nervous system were first recognized at day 1 post-natal, in the dorsal horn of the spinal cord. At day 2, the first galanin-immunoreactive neuronal somata were visualized in several regions of the diencephalon; at later stages of maturation positive cells were also detected in many brain stem areas. The number, density and staining intensity of galanin-positive structures in these and other regions increased steadily until day 28, by which age the adult disposition was attained. Increases in the concentrations of galanin-like immunoreactivity during maturation of the animals closely paralleled the immunohistochemical findings. No reduction in galanin-like immunoreactivity was noted in any area during later post-natal ages. The present study indicates that the ontogeny of galanin-like immunoreactivity in the rat central nervous system occurs entirely post-natally. The developmental profile is consistent with the role of galanin as a putative neurotransmitter/neuromodulator in the rat brain and spinal cord.

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

“…The list of probable functions involving GAL can even be bigger. Since the differentiation of the galaninergic system occurs early in the developing mammalian brain, a role of GAL in CNS differentiation has also been suggested (Sizer et al, 1990;Elmquist et al, 1992). The role of GAL in the CNS of nonmammalian vertebrates A.-J.…”

Expression of mRNA for galanin, galanin-like peptide and galanin receptors 1–3 in the ovine hypothalamus and pituitary gland: effects of age and gender

“…Due to its widespread distribution within the central nervous system (CNS), it has been proposed that galanin is involved in the regulation of a number of physiological processes, including nutrition, growth and reproduction (Crawley et al 1993, Cheung et al 1996, Baratta et al 1997, Shen et al 1998, Chaillou & Tillet 2005. Reported changes in galanin expression during foetal and post-natal development in the rat, human and opossum also suggest that galanin may be involved in the developmental differentiation of the foetal brain (Sizer et al 1990, Elmquist et al 1992, Bhide & Puranik 2005.…”

Transmitter plasticity in the developing brain

“…For example, during development noradrenergic traits were detected on embryonic day 12.5 in the rat [Specht et al, 1981], before synaptogenesis [Lauder and Bloom, 1974b] and neural transmission are occurring in this brain region. On the other hand, the co-localized peptide, galanin, was first detected on postnatal day 11 [Sizer et al, 1990], a time when these cells are receiving afferent innervation [Lauder and Bloom, 1974a] and projecting widely to targets in the CNS [Loy and Moore, 1979]. It is intriguing to consider that the initial expression of peptides may be influenced by these neuron-neuron signals, while initial expression of noradrenergic traits may be regulated by other signals.…”