DISTRIBUTION OF GALANIN-LIKE IMMUNOREACTIVITY IN THE BRAIN OF THE TURTLE MAUREMYS-CASPICA

Galanin is a brain-gut peptide present in the central nervous system o f fish, amphibians, birds, and mammals. For comparative studies among vertebrates, the distribution of galanin in the brain of reptiles has been investigated. We studied the localization of galanin-like-immunor eactive perikarya and nerve fibers in the brain of the turtle Mauremys caspica by using an antiserum against porcine galanin. In the telence phalon, few immunoreactive perikarya were seen in the amygdaloid compl ex. The diencephalon contained the majority of the immunoreactive peri karya present in the lamina terminalis, nucleus periventricularis ante rior, lateral preoptic area, nuclei hypothalamicus ventromedialis and posterior, nucleus basalis of the anterior commissure, and nucleus ven tralis tuberis. Many immunoreactive cells, especially in the infundibu lum, contacted the cerebrospinal fluid by an apical process. In the rh ombencephalon, immunopositive perikarya were restricted to a few cells in the nucleus tractus solitari. In the mesencephalon, they were abse nt. Immunoreactive nerve fibers were present in all regions containing labeled perikarya and in 1) telencephalon: septum, nucleus fasciculi diagonalis Brocae; 2) diencephalon: nucleus paraventricularis, nucleus supraopticus, nucleus suprachiasmaticus, subventricular grey, nucleus of the paraventricular organ, nucleus mamillaris, infundibular decuss ation, outer layer of the median eminence, posterior commissure and su bcommissural organ region, habenula, nuclei dorsomedialis anterior, an d dorsolateralis anterior of the thalamus; and 3) mesencephalon and rh ombencephalon: stratum griseum periventriculare, stratum fibrosum peri ventriculare, laminar nucleus of the torus semicircularis, periventric ular grey, nucleus interpeduncularis, nucleus ruber, substantia nigra, locus coeruleus, raphe nuclei, nuclei of the reticular formation, nuc leus motorius nervi trigemini, cochlear and vestibular area, and nucle us spinalis nerve trigemini. Our results suggest that galanin may have hypophysiotropic and central roles in the turtle Mauremys caspica. (C ) 1994 Wiley-Liss, Inc.