GALANIN-LIKE IMMUNOREACTIVE EXPRESSION IN THE CENTRAL-NERVOUS-SYSTEM OF THE TOAD

The distribution of galanin (GAL)-like immunoreactivity (-LI) was stud ied in the CNS of the toad (Bufo arenarum Hensel). Tissue sections wer e incubated with antibodies directed toward rat or porcine GAL and pro cessed either for the avidin-biotin complex, or for the indirect immun ofluorescence techniques. In the telencephalon GAL-immunoreactive (-IR ) perikarya were observed in the ventral part of the striatum and in t he septal accumbens nuclei. Immunopositive neurons were also observed in the medial amigdala with some intermingled cells between the fibers of the anterior commissure. Numerous GAL-IR perikarya were present al ong the rostrocaudal medial preoptic nucleus. Occasionally lightly imm unoreactive cells were detected in the magnocellular region. The most numerous accumulation of GAL-IR cells was present in the ventral hypot halamus around the infundibular region, in the posterior tubercle and in the nucleus of the paraventricular organ. Immunostained cells were also present in the pretectal gray, solitary nucleus, gracil nucleus a nd in the spinal cord in the intermediate gray and in large motoneuron s of the ventral horn. The widespread distribution found of GAL-LI sug gests that GAL in the toad, as well as in mammalian species, may serve a variety of functions with a preponderant role in neuroendocrine pro cesses. A role for GAL as a trophic factor in the brain of the toad is also suggested.