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Postnatal development of [D‐Ala 2 ]deltorphin‐I‐like immunoreactive structures in the rat brain
Author(s) -
omura Kazuo,
Tooyama Ikuo,
Abe Hiromichi,
Renda Tindaro,
Erspamer Vittorio,
Shimada Morimi,
Kimura Hiroshi
Publication year - 1994
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.903490206
Subject(s) - olfactory tubercle , ventral pallidum , ventral tegmental area , anterior olfactory nucleus , biology , pars compacta , olfactory bulb , superior colliculus , dorsal raphe nucleus , substantia nigra , anatomy , neuroscience , nucleus accumbens , midbrain , globus pallidus , central nervous system , dopamine , basal ganglia , dopaminergic , receptor , serotonin , biochemistry , serotonergic
Abstract [D‐Ala 2 ]deltorphin‐I, a highly selective ligand for δ opioid receptors, is a heptapeptide originally purified from frog skin. Previous immunohistochemical studies indicate that [D‐Ala 2 ]deltorphin‐I‐like molecule(s) may be present in adult rat brain, including specific neuronal cells and fibers partially overlapping with the mesocortical and nigrostriatal dopaminergic systems. Here, we examined the developmental aspect of such immunoreactive brain structures in early postnatal rats. In newborn to 21‐day‐old rats, positive staining in the brain occurred mainly in subpopulations of neurons and occasionally in tanycytes. On postnatal day 0, neuronal cell bodies containing [D‐Ala 2 ]deltorphin‐I‐like immunoreactivity were found in various brain regions, including the olfactory tubercle, ventral pallidum, hippocampus, ventral tegmental area, pars compacta of the substantia nigra, supramammillary nucleus, and dorsal raphe nucleus. Immunoreactive nerve fibers were observed in the main and accessory olfactory bulbs, olfactory tubercle, prelimbic area, anterior cingulate cortex, neostriatum, accumbens, lateral septal nucleus, lateral habenular nucleus, and superior colliculus. As pups grew, positive staining of cell bodies decreased gradually in both density and intesity, and those in the olfactory tubercle and ventral pallidum were no longer visible on postnatal day 14. On postnatal day 21, positive cells were found only in the ventral midbrain, including the pars compacta of the substantia nigra, ventral tegmental area, A8 region, and supramammillary nucleus. Positive fibers also decreased in density with age except in the accessory olfactory bulb, olfactory tubercle, prelimbic area, and anterior cingulate cortex. © 1994 Wiley‐Liss, Inc.