Galanin in a parasympathetic ganglion

Abstract

Galanin, a 29-amino acid peptide originally isolated from pig intestine, is now known to be present in neuronal cell bodies and fibers in many regions of both the peripheral and central nervous systems (Tatemoto et aL, 1983; Rokaeus, 1987). In the peripheral nervous system, galanin has been reported in numerous locations. An extensive galanin innervation has been demonstrated in the enteric nervous system across mammalian and non-mammalian species (Rokaeus et aL., 1984; Bishop et al., 1986; Melander et al., 1985; Bauer et al., 1988; Hoyle and Burnstock, 1989; Morris et al., 1989; McKeon and Parsons, 1990). Sensory and motor neurons as well as autonomic neurons exhibit galanin-immunoreactivity in many mammalian species (Ch’ng et al., 1985; Lundberg and Hokfelt, 1986; Lindh et al., 1989; Moore, 1989). Further, nerve fibers exhibiting galanin-immunoreactivity have also been observed in a variety of target tissues richly innervated by autonomic postganglionic axons, although the origin of these fibers has not always been established (Cheung et al., 1985; Grunditz et al., 1988; Luts et al., 1989). Galanin-immunoreactive neurons have been found in a number of different sympathetic ganglia in mammalian species (Kummer, 1988; Lindh et al., 1989); whereas only a limited number of parasympathetic ganglion cells have been reported to be galanin-immunoreactive (Grunditz et al., 1988; Frierson et al., 1989). In contrast, cells in a number of amphibian parasympathetic ganglia exhibit galanin-immunoreactivity (Morris et al., 1989; Parsons et al., 1989). We initially reported that parasympathetic cardiac neurons in the mudpuppy, Necturus maculosus, are galanin-immunoreactive (Parsons et al., 1989). In the toad, Bufo marinus, galanin-immunoreactive postganglionic neurons have been demonstrated in a variety of parasympathetic ganglia, including the cardiac ganglion (Morris et al. 1989). We also have recently reported numerous immunoreactive intrinsic neurons in the mudpuppy bladder and an extensive innervation of the bladder musculature by galanin-positive fibers (McKeon et al.,1990).