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Giuditta A, Zucconi GG, Sadile A. Brain Metabolic DNA: A Long Story and Some Conclusions. Mol Neurobiol 2022; 60:228-234. [PMID: 36251232 DOI: 10.1007/s12035-022-03030-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 09/09/2022] [Indexed: 11/26/2022]
Abstract
We have previously outlined the main properties of brain metabolic DNA (BMD) and its involvement in circadian oscillations, learning, and post-trial sleep. The presence of BMD in certain subcellular fractions and their behavior in cesium gradients have suggested that BMD originates from cytoplasmic reverse transcription and subsequently acquires a double-stranded configuration. More recently, it has been reported that some DNA sequences of cytoplasmic BMD in learning mice are different from that of the control animals. Furthermore, BMD is located in vicinity of the genes involved in different modifications of synaptic activity, suggesting that BMD may contribute to the brain's response to the changing environment. The present review outlines recent data with a special emphasis on reverse transcription of BMD that may recapitulate the molecular events at the time of the "RNA world" by activating mitochondrial telomerase and generating RNA templates from mitochondrial transcripts. The latter unexpected role of mitochondria is likely to promote a better understanding of mitochondrial contribution to cellular interactions and eukaryotic evolution. An initial step regards the role of human mitochondria in embryonic BMD synthesis, which is exclusively of maternal origin. In addition, mitochondrial transcripts involved in reverse transcription of BMD might possibly reveal unexpected features elucidating mitochondrial involvement in cancer events and neurodegenerative disorders.
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Affiliation(s)
- Antonio Giuditta
- Accademia Di Scienze Fisiche E Matematiche, Via Mezzocannone 8, 80134, Napoli, Italy.
| | | | - Adolfo Sadile
- Dept Experimental Medicine, Medical School, University Campania "L. Vanvitelli", Via S. Andrea delle Dame 7, 80138, Naples, Italy
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2
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Giuditta A, Grassi Zucconi G, Sadile A. Brain metabolic DNA: recent evidence for a mitochondrial connection. Rev Neurosci 2020; 32:/j/revneuro.ahead-of-print/revneuro-2020-0050/revneuro-2020-0050.xml. [PMID: 32866135 DOI: 10.1515/revneuro-2020-0050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 07/18/2020] [Indexed: 02/24/2024]
Abstract
This review highlights recent data concerning the synthesis of brain metabolic DNA (BMD) by cytoplasmic reverse transcription and the prompt acquisition of the double-stranded configuration that allows its partial transfer to nuclei. BMD prevails in the mitochondrial fraction and is present in presynaptic regions and astroglial processes where it undergoes a turnover lasting a few weeks. Additional data demonstrate that BMD sequences are modified by learning, thus indicating that the modified synaptic activity allowing proper brain responses is encoded in learning BMD. In addition, several converging observations regarding the origin of BMD strongly suggest that BMD is reverse transcribed by mitochondrial telomerase.
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Affiliation(s)
- Antonio Giuditta
- Accademia di Scienze Fisiche e Matematiche, Via Mezzocannone 8, Naples, I-80134,Italy
| | | | - Adolfo Sadile
- Department of Experimental Medicine, L. Vanvitelli Medical School, University Campania, Via S. Andrea delle dame 7, Naples, I-80138,Italy
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Prisco M, Casalino J, Cefaliello C, Giuditta A. Brain Metabolic DNA Is Reverse Transcribed in Cytoplasm: Evidence by Immunofluorescence Analysis. Mol Neurobiol 2019; 56:6770-6776. [PMID: 30919215 DOI: 10.1007/s12035-019-1569-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/18/2019] [Indexed: 10/27/2022]
Abstract
In a previous study (Mol Neurobiol 55:7476-7486, 2017), newly synthesized brain metabolic DNA (BMD) from rat subcellular fractions has been shown to behave as a DNA-RNA hybrid when analyzed in cesium gradients at early [3H] thymidine incorporation times but to assume the double-stranded configuration at later times. Conversely, BMD from purified nuclei displayed the dsDNA configuration even at early incorporation times. The results were interpreted to support the BMD origin by reverse transcription in the cytoplasm and its later acquisition of the double-stranded configuration before the partial transfer to the nuclei. This interpretation has now been confirmed by immunofluorescence analyses of newly synthesized BrdU-labeled BMD from the mouse brain that demonstrates its cytoplasmic localization and colocalization with DNA-RNA hybrids. In addition, BrdU-labeled BMD has been shown to colocalize with astroglial anti-GFAP antibodies and with presynaptic anti-synaptophysin antibodies.
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Affiliation(s)
- Marina Prisco
- Biology Department, University of Naples Federico II, Complesso Universitario Monte Sant'Angelo, Via Cinthia, 80126, Naples, Italy
| | - Joyce Casalino
- Biology Department, University of Naples Federico II, Complesso Universitario Monte Sant'Angelo, Via Cinthia, 80126, Naples, Italy
| | - Carolina Cefaliello
- Department of Neurology, University of Massachusetts Medical School, Albert Sherman Center 6-1008, 368 Plantation St., Worcester, MA, 01605, USA
| | - Antonio Giuditta
- Accademia di Scienze Fisiche e Matematiche, Via Mezzocannone 8, 80134, Naples, Italy.
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Cefaliello C, Prisco M, Crispino M, Giuditta A. DNA in Squid Synaptosomes. Mol Neurobiol 2018; 56:56-60. [PMID: 29675577 DOI: 10.1007/s12035-018-1071-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/09/2018] [Indexed: 11/26/2022]
Abstract
The synthesis of brain metabolic DNA (BMD) is modulated by learning and circadian oscillations and is not involved in cell division or DNA repair. Data from rats have highlighted its prevalent association with the mitochondrial fraction and its lack of identity with mtDNA. These features suggested that BMD could be localized in synaptosomes that are the major contaminants of brain mitochondrial fractions. The hypothesis has been examined by immunochemical analyses of the large synaptosomes of squid optic lobes that are readily prepared and identified. Optic lobe slices were incubated with 5-bromo-2-deoxyuridine (BrdU) and the isolated synaptosomal fraction was exposed to the green fluorescent anti-BrdU antibody. This procedure revealed that newly synthesized BrdU-labeled BMD is present in a significant percent of the large synaptosomes derived from the nerve terminals of retinal photoreceptor neurons and in synaptosomal bodies of smaller size. Synaptosomal BMD synthesis was strongly inhibited by actinomycin D. In addition, treatment of the synaptosomal fraction with Hoechst 33258, a blue fluorescent dye specific for dsDNA, indicated that native DNA was present in all synaptosomes. The possible role of synaptic BMD is briefly discussed.
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Affiliation(s)
- Carolina Cefaliello
- Department of Biology, University of Naples Federico II, Via Cinthia, 80126, Naples, Italy
- Department of Neurology, University of Massachusetts Medical School, Albert Sherman Center 6-1008, 368 Plantation St., Worcester, MA, 01605, USA
| | - Marina Prisco
- Department of Biology, University of Naples Federico II, Via Cinthia, 80126, Naples, Italy
| | - Marianna Crispino
- Department of Biology, University of Naples Federico II, Via Cinthia, 80126, Naples, Italy
| | - Antonio Giuditta
- Department of Biology, University of Naples Federico II, Via Cinthia, 80126, Naples, Italy.
- Accademia di Scienze Fisiche e Matematiche, Via Mezzocannone 8, 80134, Naples, Italy.
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5
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Abstract
Brain metabolic DNA (BMD) is not involved in cell division or DNA repair but is modulated by memory acquisition, sleep processing, and circadian oscillations. Using routine methods of subcellular fractionation, newly synthesized BMD from male rats is shown to be localized in crude nuclear, mitochondrial, and microsomal fractions and in two fractions of purified nuclei. Sub-fractionation of the mitochondrial fraction indicates the prevalent localization of BMD in free mitochondria and to a lesser degree in synaptosomes and myelin. Cesium density profiles of homogenate, subcellular fractions, and purified nuclei obtained after incorporation periods from 30 min to 4 h indicate that BMD synthesis takes place by reverse transcription in cytoplasmic organelles. Following the acquisition of the double-stranded structure, BMD is transferred to nuclei. Kinetic analyses lasting several weeks highlight the massive BMD turnover in subcellular fractions and purified nuclei and its dependence on age. Data are in agreement with the role of BMD as a temporary information store of cell responses of potential use in comparable forthcoming experiences.
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Giuditta A, Grassi-Zucconi G, Sadile AG. Brain metabolic DNA in memory processing and genome turnover. Rev Neurosci 2017; 28:21-30. [DOI: 10.1515/revneuro-2016-0027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 07/15/2016] [Indexed: 11/15/2022]
Abstract
AbstractSophisticated methods are currently used to investigate the properties of brain DNA and clarify its role under physiological conditions and in neurological and psychiatric disorders. Attention is now called on a DNA fraction present in the adult rat brain that is characterized by an elevated turnover and is not involved in cell division or DNA repair. The fraction, known as brain metabolic DNA (BMD), is modulated by strain, stress, circadian oscillations, exposure to enriched or impoverished environment, and notably by several training protocols and post-trial sleep. BMD is frequently localized in glial cells but is also present in neurons, often in the perinucleolar region. Its distribution in repetitive and non-repetitive DNA fractions shows that BMD differs from native DNA and that in learning rats its profile differs from that of control rats. More detailed knowledge of the molecular, cellular, and time-dependent BMD features will be necessary to define its role in memory acquisition and processing and in the pathogenesis of neurologic disorders.
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Affiliation(s)
- Antonio Giuditta
- 1Department of Biology, Federico II University, Via Mezzocannone 8, I-80134 Napoli, Italy
| | - Gigliola Grassi-Zucconi
- 2Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, I-37129 Verona, Italy
| | - Adolfo G. Sadile
- 3Department of Experimental Medicine, Second University of Naples, Via S. Andrea delle dame 7, I-80138 Naples, Italy
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7
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Grassi Zucconi G, Cipriani S, Balgkouranidou I, Scattoni R. 'One night' sleep deprivation stimulates hippocampal neurogenesis. Brain Res Bull 2006; 69:375-81. [PMID: 16624668 DOI: 10.1016/j.brainresbull.2006.01.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 01/20/2006] [Accepted: 01/20/2006] [Indexed: 12/20/2022]
Abstract
Neurogenesis in the adult hippocampus can be up- or downregulated in response to a variety of physiological and pathological conditions. Among these, dysregulation of hippocampal neurogenesis has been recently implicated in the pathogenesis of depression. In addition, in animal models of depression, a variety of antidepressant treatments reverse that condition by increasing neurogenesis. As one night sleep deprivation is known to improve mood in depressed patients for at least 1 day, we investigated whether a comparable treatment may affect hippocampal neurogenesis in adult rats. Accordingly, rats were sleep-deprived by gentle handling for 12 h during their physiological period of rest, and were injected with bromodeoxyuridine 4 h and 2 h before the end of sleep deprivation. They were then perfused immediately thereafter, or after 15 days and 30 days. We found that 12 h sleep deprivation significantly increased cell proliferation and the total number of surviving cells in the hippocampal dentate gyrus soon after sleep deprivation, as well as 15 days and 30 days later, in comparison to control rats allowed to sleep. No changes were instead found in the subventricular zone of the lateral ventricles, indicating that 12 h sleep deprivation selectively triggers neurogenic signals to the hippocampus. The present data include acute sleep deprivation among the conditions which upregulate hippocampal neurogenesis and raise the possibility that such response could be implicated in the beneficial effects elicited in depressed patients by one night sleep deprivation. Thus, the findings could contribute to the understanding of the intriguing relationship between depression and neurogenesis in the adult brain.
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Abstract
For a long time, the occurrence of neurogenesis in the adult mammalian brain was deemed non-existent or, at best, restricted to phylogenetically old brain regions. The pendulum of current opinion has now swung in the opposite direction with growing awareness that incorporation of labeled precursors into neuronal DNA occurs widely in the brain, and undergoes significant modulation with learning, different kinds of experiential inputs, and a number of physiological manipulations. A thorough review of the literature indicates that unscheduled DNA synthesis may significantly contribute to available evidence. Notably, data interpreted in terms of nerve cell turnover are more likely to reflect turnover of neuronal DNA, as suggested by earlier investigations.
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Nakanishi H, Sun Y, Nakamura RK, Mori K, Ito M, Suda S, Namba H, Storch FI, Dang TP, Mendelson W, Mishkin M, Kennedy C, Gillin JC, Smith CB, Sokoloff L. Positive correlations between cerebral protein synthesis rates and deep sleep in Macaca mulatta. Eur J Neurosci 1997; 9:271-9. [PMID: 9058047 DOI: 10.1111/j.1460-9568.1997.tb01397.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Local rates of cerebral protein synthesis (ICPSleu) were determined with the autoradiographic L-[1-14C]leucine method in seven awake and seven asleep, adult rhesus monkeys conditioned to sleep in a restraining chair in a darkened, ventilated chamber while EEG, EOG, and EMG were monitored. Prior to the period of measurement all animals slept for 1-4 h. Controls were awakened after at least one period of rapid-eye-movement (REM) sleep. Experimental animals were allowed to remain asleep, and they exhibited non-REM sleep for 71-99% of the experimental period. Statistically significant differences in ICPSleu between control and experimental animals were found in four of the 57 regions of brain examined, but these effects may have occurred by chance. In the sleeping animals, however, correlations between ICPSleu and percent time in deep sleep were positive in all regions and were statistically significant (P < or = 0.05) in 35 of the regions. When time in deep sleep was weighted for the integrated specific activity of leucine in grey matter, positive correlations were statistically significant (P < or = 0.05) in 18 regions in the experimental animals. These results suggest that rates of protein synthesis are increased in many regions of the brain during deep sleep compared with light sleep.
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Affiliation(s)
- H Nakanishi
- Laboratory of Cerebral Metabolism, National Institute of Mental Health, Bethesda, MD 20892-4030, USA
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10
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Sadile AG, Neugebauer A, Giuditta A. Unscheduled brain DNA synthesis, long-term potentiation, and depression at the perforant path-granule cell synapse in the rat. Brain Res Bull 1995; 36:333-41. [PMID: 7712192 DOI: 10.1016/0361-9230(94)00190-c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We investigated the effect of long-term potentiation (LTP) of the perforant path-granule cell synapse, on the synthesis of DNA in the target area and in polysynaptically stimulated hippocampal (CA3/CA1) and cortical areas (entorhinal, temporal, and occipital cortices) in the rat. The contralateral nonstimulated side was used as a control. The degree of LTP was indexed by the field EPSP and population spike amplitude recorded in the dentate area of the stimulated side before and after high frequency stimulation (250 Hz, 250 ms) every 30 min. DNA synthesis was evaluated in tissue homogenates after a 3-h period of incorporation of 3H-thymidine. DNA synthesis was significantly lower in the stimulated side in the hippocampal cortex CA3/CA1 (-25%), and in the entorhinal cortex (-50%), but not in the dentate area. In addition, the occurrence of preparations without expression of LTP allowed the analysis of unscheduled brain DNA synthesis (UBDS) in a supposedly long-term depression (LTD) subgroup. UBDS was higher in the group without LTP (no-LTP group) than in that with a significant LTP expression (LTP-group) on both sides of the brain. Furthermore, correlative analyses revealed that UBDS covaried with LTP of the EPSP (but not of population spike) in the dentate area and in extratarget hippocampal subregions on both sides and in dorsal cortex on the stimulated side. Further, regional crosscorrelation analyses revealed a high degree of coupling among brain sites following LTP.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- A G Sadile
- Department Human Physiology F. Bottazzi, Second University of Naples (SUN), Italy
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Sadile AG, Cerbone A, Lamberti-D'Mello C, Amoroso S, Annunziato L, Menna T, Buono C, Rafti F, Giuditta A. The dorsal noradrenergic bundle modulates DNA remodeling in the rat brain upon exposure to a spatial novelty. Brain Res Bull 1995; 37:9-16. [PMID: 7606484 DOI: 10.1016/0361-9230(94)00251-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A series of experiments were designed to study the role of the dorsal noradrenergic bundle (DNB) in the modulation of genomic remodeling in the mammalian brain. A series of experiments were designed to study the role of the dorsal noradrenergic system in relation to nonassociative tasks. Adult male Sprague-Dawley rats were either bilaterally lesioned in the DNB by intrabundle microinjection of 6-hydroxydopamine or were sham lesioned. All rats were given 50 microCi [3H-methyl]-thymidine and were sacrificed 0.5 h later. After the injection of the tracer, rats were either left undisturbed in the home cage or were exposed to a Làt-maze for 15 min after 15 min had passed from the time of injection. During the exposure to the maze, corner crossings and rearings were monitored. The rate of DNA synthesis was determined in several brain regions by measuring the amount of tracer incorporated into the DNA over a 0.5-h duration pulse. Under baseline conditions DNB-lesioned rats showed an increase in DNA synthesis in the hippocampus, hypothalamus, and rest of the brain. On the other hand, following exposure to the Làt-maze, sham-lesioned rats only showed an increase in DNA synthesis in the hippocampus, as compared to baseline conditions. Conversely, DNB-lesioned rats did not show an increase in hippocampal DNA synthesis as in the sham-lesioned rats. In contrast, DNA synthesis was increased in the neocortex and rest of the brain. In conclusion, the data support a role for noradrenergic systems in modulating brain DNA synthesis, probably of the unscheduled type, during information processing and storage.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- A G Sadile
- Department of Human Physiology F. Bottazzi, Second University of Naples (SUN), Italy
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12
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Zhang R, Lu Z, Liu T, Soong SJ, Diasio RB. Circadian rhythm of rat spleen cytoplasmic thymidine kinase. Biochem Pharmacol 1993; 45:1115-9. [PMID: 8461041 DOI: 10.1016/0006-2952(93)90256-v] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The activity of thymidine kinase (TK, EC 2.7.1.21), the first enzyme of the thymidine phosphorylation pathway, was measured at various times over a 24-hr period in the spleens of Sprague-Dawley rats that had been housed under standardized conditions of light and dark for at least 4 weeks before the study. Spleen cytoplasmic TK activity was assayed with [2-14C]thymidine as substrate. Under "normal" light conditions (lights on 6:00 a.m.-6:00 p.m. and lights off 6:00 p.m.-6:00 a.m.), a circadian variation of TK activity was observed (P < 0.0001), Cosinor analysis) with peak activity (1.98 nmol product/hr/mg protein) at 1:00 a.m. (19 hr after light onset, HALO) and trough activity (0.40 nmol product/hr/mg protein) at 1:00 p.m. (7 HALO). Maximum enzyme activity exceeded minimum activity by approximately 5-fold. Reversing the light-dark cycle resulted in a corresponding shift in TK activity. Under these "reverse" conditions (lights on 6:00 p.m.-6:00 a.m. and lights off 6:00 a.m.-6:00 p.m.), a circadian variation in TK activity was also observed (P < 0.0001, Cosinor analysis) with peak activity (1.14 nmol product/hr/mg protein) at 12:00 noon (18 HALO) and trough activity (0.32 nmol/hr/mg protein) at 12:00 a.m. (6 HALO). Maximum enzyme activity exceeded minimum activity by approximately 4-fold. In summary, this study demonstrated for the first time that TK activity varies over a 24-hr period in association with the light-dark cycle.
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Affiliation(s)
- R Zhang
- Department of Pharmacology, University of Alabama, Birmingham 35294
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Sadile AG, Neugebauer A, Morelli F, Horvath Z, Buzsàki G, Giuditta A. Distributed changes in rat brain DNA synthesis with long-term habituation and potentiation of the perforant path-granule cell synapse. Behav Brain Res 1991; 46:83-94. [PMID: 1786115 DOI: 10.1016/s0166-4328(05)80099-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The involvement of brain deoxyribonucleic acid (DNA) synthesis in adaptive neural events was studied in the adult rat during long-term habituation (LTH) or potentiation (LTP) of the perforant path-granule cell synapse. Male Long-Evans rats were given 50 muCi [3H]thymidine intraventricularly under urethane anesthesia. Soon thereafter, field excitatory postsynaptic potential (EPSP) slope and population spike were monitored from the right dentate gyrus before and at various times (5, 10, 15, 60 min) following the delivery to the ipsilateral perforant bundle of a low frequency (LFS: 1.0 Hz, 160 s) or a high-frequency train (HFS: 400 Hz, 200 ms), repeated once after 5 min. Unstimulated implanted rats served as controls. DNA synthesis was evaluated by the incorporation of the radioactive precursor into DNA of several brain areas at the end of a 1 h incorporation period. In CA1, LTH and LTP increased DNA synthesis by 30% on the stimulated side. In the entorhinal cortex, LTH but not LTP increased DNA synthesis (by 30%) on the stimulated side. Conversely, in the frontal cortex, LTP but not LTH increased DNA synthesis (by 100%) on both sides. Long-lasting changes in synaptic efficacy covaried non-linearly with DNA synthesis in mono- and polysynaptically stimulated hippocampal regions, and in functionally associated neocortical areas. The co-variations of population spike amplitude were positive for LTH and negative for LTP in the dentate gyrus and frontal cortex of both sides, and in CA3/CA1 of the stimulated side, indicating higher DNA synthesis at lower values of LTH and LTP, and viceversa. Further, regional cross-correlation analyses revealed a high degree of synchronization among brain sites, following low- or high-frequency train pulses, indicating that (i) extra-target sites participate on the stimulated and on the contralateral side, and (ii) small distributed changes take place across the sampled neural networks. A modulatory role of information flow on brain DNA synthesis is inferred to take place in a diffuse, distributed manner.
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Affiliation(s)
- A G Sadile
- Dipt. Fisiologia Umana e Funzioni Biologiche Integrate F. Bottazzi, Naples, Italy
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