PCNA-negativity in the telencephalon of adul female songbirds (Serinus serinus): absence of signs of normal proliferation

In a recent study, we demonstrated the persistence of normal proliferation in the telencephalon of adult male songbirds (Serinus serinus), as shown by the expression of Proliferating Cell Nuclear Antigen (PCNA), a test that uses monoclonal antibodies to reveal cells in the S phase. Near the start of the breeding season, this proliferation was observed in circumscribed areas of the ventricular ependymal epithelium (zona germinativa dorsalis and zona germinativa ventralis) and in small masses of cells that were grouped or separated ("hot spots"). Therefore, we decided to extend this research to normal adult females of the species, using the same marker and the same time period as in the previous study. This time, however, we did not observe PCNA-positivity, and thus any sign of natural proliferation, in the telencephalic areas that showed it in the male songbirds. The immunocytochemical patterns recorded in females and males of Serinus serinus agree with the information reported in the literature, namely that in adult homeothermic Vertebrates the presence of spontaneous cerebral neurogenesis is limited to male songbirds

Signs of normal proliferation in the telencephalon od adult male songbirds (Serinus serinus), as shown by PCNA-positivity

The immunocytochemical expression of Proliferating Cell Nuclear Antigen (PCNA) (a cycline that coadjuvates DNA polymerase delta) becomes appreciable in the cell cycle when DNA synthesis occurs; hence cells in the S phase can be revealed by means of monoclonal antibodies. Therefore, PCNA can be considered a marker of proliferation, and numerous literature reports have demonstrated the reliability of the PCNA test. Since normal neurogenic events can still occur in the brain tissue of adult homeothermic vertebrates (especially songbirds), we evaluated if the persistence of spontaneous proliferation could be revealed in adult male songbirds (Serinus serinus) using the PCNA marker, the same test we used previously to study the persistence of natural proliferation in the encephalon of adult heterothermic vertebrates. The patterns of PCNA positivity showed normal proliferation in the telencephalon of the adult male Serinus serinus. This activity was shown by cells interposed among the epithelial cells lining the lateral side of each ventricular cavity, both in correspondence to the apical tracts and declivities of the ependyma and arranged, here and there, either in groups or slightly separated. As in our previous studies on PCNA expression and persistence of spontaneous encephalic proliferation in adult poikilothermal vertebrates (in the telencephalon of Podarcis, Triturus and Rana, and in the telencephalon, mesencephalon and cerebellum of Carassius), the results of the present research largely agree with the findings of previous Authors, usually obtained with different methods. This agreement confirms the reliability of the PCNA test used for this type of investigation

PCNA immunoreactivity revealing normal proliferative activity in the brain of adult Lampetra planeri (Bloch, 1784)

It is now well known that the Teleosts among Osteichthyes, Urodele and Anuran Amphibians, Lacertilian Reptiles possess encephalic natural proliferative activities even into adulthood, as demonstrated by a great number of researches performed both under normal and various experimental conditions. Few years ago we have undertaken in adult heterothermic vertebrates a reappraisal on spontaneous cerebral proliferative events involving some organisms (Podarcis sicula, Triturus carnifex, Rana esculenta, Carassius carassius) representative of these vertebrates and belonging to the same or phylogenetically similar species used by previous researchers in studies having the same object. In our investigations, these performances were revealed by a proliferative immunocytochemical marker, the Proliferating Cell Nuclear Antigen (PCNA). At this point of our study in the scenario emerging from findings a missing piece is represented by Petromyzontidae. To fill up this gap in the present investigation, using our usual test, we have paid attention to adult specimens of Lampetra planeri. The obtained immunostaining panorama has revealed the presence of a considerable number of spontaneous proliferative activities. These events might differ in quantity, in various encephalic districts. PCNA-labelled cells appeared scattered in the cranial portion of olfactory bulbs, while the PCNA expression has been observed steadily localized with a distinctly continous distribution in cells interposed among the ependymal epithelium which lines the cavities of the proximal portion of the olfactory region and of the cerebral ventricles. DNA synthesis activity has been also found in cells scattered in the telencephalic, diencephalic, mesencephalic and medulla oblongata periventricular grey. This immunoreactivity was not revealable in the cerebellum. Our findings are discussed in the light of bibliographic news

Dopamine receptor mRNAs in the rat lymphocytes

i.f. (2001) 1.75

Dopamine receptor mRNAs in the rat lymphocytes.

i.f. (2001) 1.75

Treatment with 6-hydroxydopamine in planaria (Dugesia gonocephala s.l.): morphological and behavioral study.

IF 0.9

Myelin basic protein induces heme oxygenase-1 in human astroglial cells

Heme oxygenase-1 (HO-1), also known as heat-shock protein 32 (HSP-32), is induced in many cells by a large variety of stimuli. Its induction in nervous system cells following toxic and oxidative stress was suggested to play a protective role. Its presence was recently detected by immunohistochemical studies at the level of inflammatory lesions of rat experimental autoimmune encephalomyelitis. In the present study, we demonstrate that myelin basic protein (MBP) induces HO-1 in human astroglial cells, as shown by Western blots and RT-PCR. Proteolytic fragments derived from the whole MBP show a different behavior in the HO-1 induction: MBP152-167 was able to produce a light but still significant increase in HO-1 mRNA and protein levels, whereas MBP68-84 was not. The increase in HO-1 production seems to be mediated by a Ca2+-dependent mechanism, since MBP addition to astrocytoma cultures induced a strong and immediate increment of [Ca2+](i) increase; MBP152-167 elicited a delayed and less pronounced [Ca2+](i) increase; no [Ca2+](i) changes were induced following cell treatment with MBP68-84. NO pathway involvement in the induction of HO-1 by MBP was ruled out since the expression of the inducible isoform of nitric oxide synthase was not upregulated in treated cells, neither nitrite levels were modified, as demonstrated by Greiss reaction. The possible significance of HO-1 induction following MBP stimulation is discussed. GLIA 37:83-88, 2002. (C) 2002 Wiley-Liss, Inc